Mr. Buist has favoured me with the following notes, which were compiled from his day-books at an early stage of the Stormontfield experiments:—
“1. Of the marked fish which were liberated from the pond at Stormontfield, four out of every hundred were recaptured, either as grilse or salmon.
“2. We find that more than 300,000 fish were reared in the pond, and allowed to go into the Tay. Thus forty fish out of every thousand were recaptured; and as 300,000 were in all liberated, it follows that 12,000 of the salmon taken in the Tay were pond-bred fish. But as the fish did not all go away in one year, this 12,000 must be distributed over two years.
“3. We find the average number of salmon and grilse taken in each year is 70,000. It follows, then, if there be any truth in figures, that nearly one-tenth of the fish taken in the Tay for the last two years were artificially bred. This is equivalent to a rise of 10 per cent in the rental of the fishings; and such we find is the result.
“It may be urged that if the salmon from which the ova were taken had been left at liberty, the result would have been the same; but this we know could not have been the case, for, according to a careful calculation made by Mr. Thomas Tod Stoddart and others, each pair of salmon, although they produce upon an average 30,000 eggs, do not rear above five fish. Three female fish, if every egg they deposit was to produce a salmon, would produce all the fish in the Tay. When left in their natural state, 30,000 ova produce four or five fish fit for the table; whereas the same number of ova, when carefully protected in the breeding-ponds, produce about 800. This is supposing that one-third of the ova deposited in the boxes perishes—does not hatch, and comes to nothing. Therefore the increase in the number of salmon taken within the last year is accounted for. Had there been any increase in the number of fish in the other rivers of Scotland, doubts might arise; but there has been no such increase, last year being a bad one for every river in Scotland with the exception of the Tay.”
In addition to the group of salmon-breeding ponds at Stormontfield, a very successful suite of breeding-boxes has been laid down on the river Dee, in the Stewartry of Kirkcudbright, by Messrs. Martin and Gillone, the lessees of the river Dee salmon-fisheries. Mr. Gillone, who is an adept in the art of fish-culture, was one of the earliest to experiment on the salmon, and so long ago as 1830 had arrived at the conclusion that parr were young salmon, and that that tiny animal changed at a given period into a smolt, and in time became a valuable table-fish. These early experiments of Mr. Gillone’s were not in any sense commercial; they were conducted solely with a view to solve what was then a curious problem in salmon-growth. In later years Mr. Gillone and his partner have entered upon salmon-breeding as an adjunct of their fisheries on the river Dee, for which, as tacksmen, they pay a rental of upwards of £1200 per annum. The breeding-boxes of Messrs. Martin and Gillone have been fitted up on a very picturesque part of the river at Tongueland, and the number of eggs last brought to maturity is considerably over 100,000. The present series of hatchings for commercial purposes was begun in 1862-63 with 25,000 eggs, followed in the succeeding year by a laying down of nearly double that number. The hatchings of these seasons were very unsuccessful, the loss from many causes being very great, for the manipulation of fish eggs during the time of their artificial extraction and impregnation requires great care—a little maladroitness being sufficient to spoil thousands.
The last hatching (spring 1865) has been most successfully dealt with. Messrs. Martin and Gillone’s breeding-boxes are all under cover, being placed in a large lumber-store connected with a biscuit manufactory. This chamber is seventy feet long, and there is a double row of boxes extending the whole length of the place. These receptacles for the eggs are made of wood; they are three feet long, one foot wide, and four inches deep, and into the whole series a range of frames has been fitted containing glass troughs on which to lay the eggs. The edges of the glass are ground off, and they are fitted angularly across the current in the shape of a V. The eggs are laid down on, or rather sown into, these troughs, from a store bottle, on to which is fitted a tapering funnel. The flow of water, which is derived from the river, and is filtered to prevent the admission of any impurity, is very gentle, being at the rate of about fifteen feet per minute, and is kept perfectly regular. The boxes are all fitted with lids, in order to prevent the eggs from being devoured, as is often done, by rats and other vermin, and also to assimilate the conditions of artificial hatching as much as possible to those of the natural breeding-beds—where, of course, the eggs are covered up with gravel and are hatched in comparative darkness.
It may be of some use, particularly to those who are interested in pisciculture, to note a few details connected with the capturing of the gravid fish and the plan of exuding the ova practised at Tongueland. The river Dee is tolerably well stocked with fish, as may be surmised from the rent I have named as being paid for the right of fishing. Mr. Gillone adopts the plan, now also in use at Stormontfield, of capturing his fish in good time—in fact, as a general rule, before the eggs are ripe—and of confining them in his mill-race till they are thoroughly ready for manipulation. Last season—i.e. in November and December 1864, and January 1865—as many as thirty-six female fish were taken for their roe, the number of milters being twenty-five, the total weight of the lot being 454 lbs., or, on the average, six and a half pounds each fish. According to rule, the weight of the female fish taken having been 283 lbs., these ought to have yielded 283,000 eggs, but as several of the fish were about ripe at the time they were caught, they spawned naturally in the mill-race, where the eggs in due time came to life. The plan of spawning pursued at Tongueland is as follows:—Whenever the fish are supposed to be ripe for that process, the water is shut out of the dam, and the animal is first placed in a box filled with water in order to its examination; if ready to be operated upon, it is then transferred to a trough filled with water about three feet and a half long, seven inches in breadth, and of corresponding depth, and the roe or milt is pressed out of the fish just in the position in which it swims. As soon as the eggs are secured, a portion of the water is poured out of the wooden vessel, and the male fish is then similarly treated. The milt and roe are mixed by hand stirring, and the eggs then being washed are distributed into the boxes.
Mr. Gillone carries on all his operations with the greatest possible precision. He has a large clear glass bottle marked off in divisions, each of which contains 800 eggs, and he numbers the divisions allotted to each particular fish, which are sown into a similarly numbered division in his box, so that by referring to his index-book he can trace out any peculiarity in the eggs, etc.
Although pisciculture has been shown by means of what has been achieved on the Continent and at Stormontfield to be eminently practical, yet nothing beyond a few toy experiments, so to speak, have been made in England; indeed, we have had a great deal of “toying” with the subject; but all honour to Messrs. Buckland and Francis—they are evidently doing their best to create public opinion on the subject. Lectures have been delivered on fish-culture, and letters have been thickly sent to the daily papers, advocating the extension of the art; but no great movement has been made beyond stocking the upper waters of the Thames with a few thousand trout and some fancy fish. Salmon also have been hatched; but can they reach the sea in the present state of the river?
