“Peter of the Pools” (Mr. Buist) says that what strikes a stranger who visits the ponds most is the great disparity in the size of fish of the same age, the difference of which can only be that of a few weeks, as all were hatched by the month of May. That there are strong and weak fry from the moment that they burst the covering admits not of a doubt, and that the early fish may very speedily be singled out from among the late ones is also quite certain. In the course of a few weeks the smolts that are to leave at the end of the first year can be noted. The keeper’s opinion is that at feeding-time the weak are kept back by the strong, and therefore are not likely to thrive so fast as those that get a larger portion of the food; he lays great stress on feeding, and his opinion on that subject is entitled to consideration.
At the time of the visit alluded to one of the ponds (the original one) was swarming with young salmon hatched out in March and April 1864, the eggs having been placed in the boxes in November and December 1863. Half of these would depart from the ponds as smolts during May 1865; the other half, I suppose, would be transferred to the new pond, as there is direct communication with both of the ponds from the canal at the foot of the suite of breeding-boxes, which have been lately renewed and improved. The requirements of spawning only once in two seasons have not been strictly observed of late years, so that eggs were laid down in both the years 1862 and 1863. In the former of those years the ova laid down were 250,000, and in 1863 about 80,000; indeed, no more could be obtained, in consequence of the river being in an unfavourable state for capturing the gravid fish.
The guiding of the smolts from the ponds to the river is easily managed through the provision made at Stormontfield for that purpose, and which consists of a runlet lined with wood, protected at the pond by a perforated zinc sluice, and terminating near the river in a kind of reception-chamber, about four feet square, which, is likewise provided with a zinc sluice (also perforated), to keep the fish from getting away till the arranged time, thus affording proper facilities for the marking and examination of departing broods. [See plan.] The sluice being lifted, the current of water is sufficiently strong to carry the fish down a gentle slope to the Tay, into which they proceed in considerable quantities, day by day, till all have departed; the parrs, strange to say, evincing no desire to remove, although, of course, being in the same breeding-ponds, they have a good opportunity of reaching the river.
It was a great drawback in former years at Stormontfield, during the hatching seasons, that many fish were caught with their eggs not sufficiently matured, and which could not be used in consequence. To remedy this, a plan has been adopted of keeping all the salmon that are caught, if they be so nearly ripe for spawning as to warrant their detention. These are confined in the mill-race till they become thoroughly ready for the manipulator, and are kept within bounds by strong iron gratings, placed about 100 yards from each other. These gravid fish are taken out as they are required, or rather as they ripen, by means of a small sweep-net, and it is noteworthy that the animals, after being once or twice fished for, become very cunning, and hide themselves in such bottom holes as they can discover, in order that the net may pass over them. I have no doubt that the Stormontfield mill-race forms an excellent temporary feeding-place for these fish, as its banks are well overhung with vegetation, and its waters are clear as crystal, and of good flavour. It is a decided convenience to be able thus to store the egg-and-milt-producing fish till they are wanted, and will render the annual filling of the breeding-boxes a certainty, which, even under the old two-year system, was not so, in consequence of floods on the river Tay, and from many other causes besides.
The latest has been the best spawning season experienced since the commencement of the Stormontfield artificial spawning operations. On the 22d of December (1865) I found that Peter Marshall, the resident pisciculturist, had up to that date deposited in the breeding-boxes more than 300,000 salmon eggs, and that he still had three adult fish to spawn, from which he calculated upon obtaining something like 50,000 additional eggs, and he told me that that number would complete the total quantity required that season—viz. 350,000; indeed, the boxes cannot conveniently hold many more, although another row has been constructed.
Upwards of a million of pond-bred fish have now been thrown into the river Tay, and the result has been a satisfactory rise in the salmon-rental of that magnificent stream.
I have compiled the following summary of what has been achieved in salmon-breeding at the Stormontfield ponds:—
On the 23d November 1853 the stocking of the boxes commenced, and before a month had expired 300,000 ova were deposited, being at the rate of 1000 to each box, of which at that time there were 300. These ova were hatched in April 1854, and the fry were kept in the ponds till May 1855, when the sluice was opened, and one moiety of the fish departed for the river and the sea. About 1300 of these were marked by cutting off the dead or second dorsal fin. The smolts marked were about one in every hundred, so that about 130,000 must have departed, leaving more than that number in the pond. The second spawning, in 1854, was a failure, only a few thousand fish being produced. This result arose from the imperfect manipulation of the fish by those intrusted with the spawning. The third spawning took place between the 22d November and the 16th December 1855, and during that time 183,000 ova were deposited in the boxes. These ova came to life in April 1856. The second migration of the fry spawned in 1853 took place between the 20th April and 24th May 1856. Of the smolts that then left the ponds, 300 were marked with rings, and 800 with cuts in the tail. Many grilses having the mark on the tail were re-taken, but none of those marked with the ring. The smolts from the hatching of 1856 left the pond in April 1857. About 270 were marked with silver rings inserted into the fleshy part of the tail; about 1700 with a small hole in the gill-cover; and about 600 with the dead fin cut off in addition to the mark in the gill-cover. Several grilses with the mark on the gill and tail were caught and reported, but no fish marked with the ring. The fourth spawning took place between the 12th November and the 2d December 1857, when 150,000 ova were deposited in the boxes. These came to life in March 1858. Of the smolts produced from the previous hatching, which left the pond in 1858, 25 were marked with a silver ring behind the dead fin, and 50 with gilt copper wire. Very few of this exodus were reported as being caught. The smolts produced from the hatching of 1858 left the pond in April 1859, and 506 of them were marked. The fifth spawning, from 15th November to 13th December 1859, produced 250,000 ova, which were hatched in April 1860. Of the smolts that left in 1860, 670 were marked, and a good many of them were reported as having been caught on their return from the sea. The smolts of the hatching of 1860 left the pond in May 1861, but none of them were marked.[2] The number of eggs deposited in the breeding-boxes in the spawning season of 1862 (November and December) was about 250,000; and in 1863 not more than 80,000 ova could be obtained, in consequence of the unfavourable state of the river for capturing gravid salmon. Peter Marshall has proved a most able pisciculturist. The loss of eggs under his management forms an almost infinitesimal proportion of the total quantities hatched at Stormontfield.