The Harvest of the Sea / A contribution to the natural and economic history of the British food fishes

by James Glass Bertram

As I have had occasion to mention the opinions of James Hogg on the salmon question, I may be allowed to state here that the following amusing bit of dialogue on the habits of the salmon once took place between the Ettrick Shepherd and a friend:—

Shepherd—“I maintain that ilka saumon comes aye back again frae the sea till spawn in its ain water.”

Friend—“Toots, toots, Jamie! hoo can it manage till do that; hoo, in the name o’ wonder, can a fish, travelling up a turbid water frae the sea, know when it reaches the entrance to its birthplace, or that it has arrived at the tributary that was its cradle?”

Shepherd—“Man, the great wonder to me is no hoo the fish get back, but hoo they find their way till the sea first ava, seein’ that they’ve never been there afore!”

The parr question, however, was determined in a rather more formal mode than that adopted by the author of “Bonny Kilmenny.” Mr. Shaw, a forester in the employment of the Duke of Buccleuch, took up the case of the parr in 1833, and succeeded in solving the problem. In order that he might watch the progressive growth of the parr, Mr. Shaw began by capturing seven of these little fishes on the 11th of July 1833; these he placed in a pond supplied by a stream of excellent water, where they grew and flourished apace till early in April 1834, between which date and the 17th of the following May they became smolts; and all who saw them on that day when they were caught by Mr. Shaw were thoroughly convinced that they were true salmon smolts. In March 1835 Mr. Shaw repeated his experiments with twelve parrs of a larger size, taken also from the river. On being transferred to the pond, these so speedily acquired the scales of the smolt that Mr. Shaw assumed a period of two years as being the time at which the change took place from the parr to the smolt. The late Mr. Young of Invershin, a well-known authority on salmon life, was experimenting at the same time as Mr. Shaw, and for the same purpose—namely, to determine if parr were the young of the salmon, and, if so, at what period they became smolts and proceeded to the sea. Well, Mr. Shaw said two years, and Mr. Young, who was at that time manager of the Duke of Sutherland’s fisheries, said the change took place in twelve months; others, again, who took an interest in the controversy, said that three years elapsed before the change was made. The various parties interested held each their own opinion, and it may even be said that the disputation still goes on; for although a numerous array of facts bearing on the migration have been gathered, we are still in ignorance of any regulating principle on which the migratory change is based, or to account for the impulse which impels a brood of fish to proceed to sea divided into two moieties. Mr. Shaw watched his young fry with unceasing care, and described their growth with great minuteness, for a period extending over two years, when his parrs became smolts. Mr. Young, in a letter from Invershin, dated January 1853, says, pointedly enough—“The fry remain in the river one whole year, from the time they are hatched to the time they assume their silvery coat and take their first departure for the sea. All the experiments we have made on the ova and fry of the salmon have exactly corresponded to the same effects, and none of them have taken longer in arriving at the smolt than the first year.”

Mr. Buist, in one of his letters on the progress of artificial breeding at the Stormontfield ponds, says: “There is at present a mystery as regards the progress of the young salmon. There can be no doubt that all in our ponds are really and truly the offspring of salmon; no other fish, not even the seed of them, could by any possibility get into the ponds. Now we see that about one half have gone off as smolts, returning in their season as grilses; the other half remain as parrs, and the milt in the males is as much developed, in proportion to the size of the fish, as their brethren of the same age seven to ten pounds weight, whilst these same parrs in the ponds do not exceed one ounce in weight. This is an anomaly in nature which I fear cannot be cleared up at present. I hope, however, by proper attention, some light may be thrown upon it from our experiments next spring. The female parrs in the pond have their ova so undeveloped that the granulations can scarcely be discovered by a lens of some power. It is strange that both Young’s and Shaw’s theories are likely to prove correct, though seemingly so contradictory, and the much-disputed point settled, that parrs (such as ours at least) are truly the young of the salmon.”

It is quite certain that parr are young salmon, and that a parr becomes a smolt and goes to the sea, although there are still to be found, no doubt, a few wrong-headed people who will not be convinced on the point, but pridefully maintain all the old salmon theories and prejudices. With them the parr is still a distinct fish, the smolt is the true young of Salmo salar in its first stage, and a grilse is just a grilse and nothing more. However, these old-world people will in time pass away (there is no hope of convincing them), and then the modern views of salmon biography, founded as they are on laborious personal investigation, will ultimately prevail.

The Smolt and Grilse.—But the great parr mystery is still unsolved—that is to say, no one knows on what principle the transformation is accomplished; how it is that only half of a brood ripen into smolts at the end of a year, the other moiety taking double that period to arrive at the same stage of progress. Some scientific visitors to the Stormontfield ponds say that this anomaly is natural enough, and that similar ratios of growth may be observed among all animals; but it is curious that just exactly the half of a brood—and the eggs be it remembered all from adult salmon, and therefore similar in ripeness and other conditions—should change into smolts at the end of a year, leaving a moiety in the ponds as parr for another twelvemonth.

The most remarkable phase in the life of the salmon is its extraordinary instinct for change. After the parr has become a smolt, it is found that the desire to visit the sea is so intense, especially in pond-bred fish, as to cause them to leap from their place of confinement, in the hope of attaining at once their salt-water goal; and of course the instinct of river-bred fish is equally strong on this point—they all rush to the sea at their proper season. There are various opinions as to the cause of the migratory instinct in the salmon. Some people say it finds in the sea those rich feeding-grounds which enable it to add so rapidly to its weight. It is quite certain that the fish attains its primest condition while it is in the salt water; those caught in the estuaries by means of stake or bag nets being richer in quality, and esteemed far before the river fish. The moment the salmon enters the fresh water it begins to decrease in weight and fall from its high condition. It is a curious fact, and a wise provision of nature, that the eel, which is also a migratory fish, descends to spawn in the sea as the salmon is ascending to the river-head for the same purpose; were the fact different, and both fish to spawn in the river, the roe of the salmon would be completely eaten up. In due time then, we find the silver-coated host leaving the rippling cradle of its birth, and adventuring on the more powerful stream, by which it is borne to the sea-fed estuary, or the briny ocean itself. And this picturesque tour is repeated year after year, being apparently the grand essential of salmon life.