THE SALMON.
At the latter end of the year, and some in November, salmon begin to press up the rivers as far as they can reach, in order to spawn; when that period approaches, and they have accommodated themselves with a fit place, nature supplies the male with a bony excrescence, growing out of the end of the lower jaw, to the length of half an inch or more: this, it is said, aids him in the removal of the gravel, but both male and female assist in forming a proper receptacle for the spawn, in the sand or gravel, about eighteen inches deep. In this the ova and milt are deposited, and carefully covered by the parent fish, who afterwards hasten to cleanse and recover themselves (the male loses the gristle at the jaw); for, after spawning, they become very poor and lean, and then are called kipper. At their first entrance into the fresh water, salmon are observed to have abundance of insects adhering to them, especially above the gills: these animals denote the fish to be in high season, and die and drop off soon after the salmon’s leaving the sea.
The spawn lies buried until spring, and, without any other care, is nourished and brought to perfection, if not disturbed by violent floods, or by depredations from other fish, of which the eel, roach, dace, and grayling, are dangerous neighbours. About the latter end of March, the spawn begins to exclude the young, which gradually increase to four or five inches in length, and are then termed smelts, or smouts; about the beginning of May the river seems to be alive, and there is no framing an idea of the numbers without seeing them. A seasonable flood, however, hurries them to the sea, very few being left in the river. About the middle of June the earliest fry commence their return from the sea into the river (at that period from twelve to sixteen inches long), and progressively augment in number and size, until about the end of July, which is, at Berwick, the height of the grilse time (the name there given to the fish of that age). Early in August they lessen in number, but advance in bigness, some being from six to as high as nine pounds’ weight. This increase appears surprisingly quick; yet a gentleman of Warrington has given an instance of still more rapid growth: a kipper salmon, weighing seven pounds three quarters, taken on the 7th of February, was marked with scissors on the back fin and tail, and turned into the river; he was again taken on the 17th of the following March, and then weighed seventeen pounds and a half. In this case the remark of Walton seems to have been more than verified, “that the samlet becomes a salmon in as short a time as a gosling becomes a goose.”
The salmon in Lough Erne increase in size wonderfully, and young ones, which were caught and marked when going into the lake, have been caught on their return, and found so large, that they must have increased at the rate of one pound per week.
The migratory habits of the salmon, and the instinct with which it periodically revisits its native river, are curious circumstances in the natural history of this fish. As the swallow returns annually to its nest, as certainly the salmon repairs to the same spot in which to deposit its ova. Many interesting experiments have established this fact. M. De Lande fastened a copper ring round a salmon’s tail, and found that for three successive seasons it returned to the same place. Dr. Bloch states, that gold and silver rings have been attached by eastern princes to salmon, to prove that a communication existed between the Persian Gulf and the Caspian and Northern Seas, and that the experiment succeeded. Shaw, in his Zoology, mentions that a salmon of seven pounds and three quarters was marked with scissors on the back fin and tail, and turned out on the 7th of February, and that it was retaken in March of the succeeding year, and found to have increased to the amazing size of seventeen pounds and a half. This statement, by the by, is at variance with the theory of Dr. Bloch, who estimates the weight of a five or six year old salmon at but ten or twelve pounds.
That the salmon should lose condition rapidly on quitting the sea for the fresh water, may be inferred from a fact agreed upon by naturalists, that during the period of spawning the fish neglects feeding. In this peculiar habit the salmon is not, however, singular; animals of the Phocæ tribe, in breeding-time, exercise a similar abstinence. On opening a salmon, at any season, no food will be discovered, and the contents of the stomach will be confined to a small quantity of yellowish fluid and tape-worms, which are generated there. Sir Humphry Davy believes that occasionally food may be found. I have seen thousands opened preparatory to being salted, and I never observed anything but this fluid and tape-worms. Another circumstance may be stated as a curious proof of health, as well as of the period of time the salmon has been resident in a river. When the fish leaves the sea, and of course is in its best condition, insects (the Lernæ Salmoneæ of Linnæus) will be perceived firmly adhering to the skin. Immediately on entering the fresh water, these insects begin to detach themselves from the salmon, and after a short time they gradually drop off and disappear.
Ireland (particularly the north) abounds with salmon; the most considerable fishery is at Crarma, on the river Ban, near Coleraine. (Some account of this fishery is mentioned in the list of the rivers, &c. of this country.) The nets used are eighteen score, or three hundred and sixty yards long, and are continually drawing, night and day, the whole season (nearly four months), two sets of sixteen men each alternately relieving one another. The best drawing is when the tide is coming in.