SALMON

(Lat. salmo.) The excellent and highly valuable fish so called in England is the Salmo salar of Linnaeus, not of Rondelet i us. Both species exist in our rivers, the latter having been recognizably and accurately defined under the name of Salmo eriox, or bull trout, which it is to be hoped will be retained for this species, notwithstanding that the name of Salmo salar may have been applied to it by the older ichthyologist. The normal locality of the salmon is at the mouth or estuary of the larger rivers, which, in the season of sexual excitement, they ascend, sooner or later, in the summer months, according as circumstances may influence their coming into breeding condition. At first they ascend only so far as the tide wave reaches, and retire with the ebb; but as the quantity of roe and milt increases, the instinct which teaches the fit locality for oviposition becomes more imperative, and few are the natural obstacles which the salmon does not overcome in its endeavour to reach it. The great value of the fish renders an accurate knowledge of it, under the disguise of its immature form and markings, of the highest importance; but the difficulties which attend the observation of the migratory inhabitants of the water have only very lately been overcome in the present instance. The proof that the small Salmonoid fish, called the parr, is, as many naturalists had suspected, the young of the salmon, has been elicited by the careful and repeated observations and experiments of Mr. Shaw of Drumlanrig, of which the following condensed account is taken from the Transactions of the Royal Society of Edinburgh. In the river Nith, Dumfries, the salmon oviposits in the month of January. On the 10th of January, Mr. Shaw observed a female salmon of about 16 lbs. weight, and two males of at least 2.5 lbs., engaged in depositing their spawn. The spot which they had selected for that purpose was a little apart from some other salmon which were engaged in the same proce , and rather nearer the side of the stream, although still in pretty deep water. The two males kept up an ince ant conflict during the whole of the day for po e ion of the female, and in their struggle frequently drove each other almost ashore, and were ref)eatedly on the surface, displaying their dorsal fins and ashing the water with their tails The female throws herself at intervals of a few minutes upon her side; and while in that position, by the rapid action of her tail she digs a receptacle in the gravel for her ova, a portion of which she deposits, and again turning upon her side she covers it up by the renewed action of the tail; thus alternately digging, depositing, and covering the ova, until the proce is completed by the laying of the whole ma , an operation which generally occupies three or four days. The embryo fish, conspicuous by the two dark eye-specks and the vascular vitelline sac, presented some appearance of animation in the ovum on February 26th, that is, forty-eight days after having been deposited; and on 8th April, or 90 days after impregnation of the ova, the young were excluded. The head is large in proportion to the body, which measures |ths of an inch in length; the vitellicle is |ths of an inch in length, and resembles a light red currant; the tail is margined like that of the tadpole, with a continuous fin running from the dorsal above to the anal beneath. The vitelline sac and its contents are absorbed by the 30th May, or in about fifty days, until which time the young fish does not leave the gravel. The terminal fringe-like fin now begins to divide itself into the dorsal, adipose, caudal, and anal fins; and the transverse bars on the sides of the body make their appearance. At this period the young salmon measures an inch in length, and is very active, and continues in the shallows of its native stream till the following 1077 SALT. spring, when it has attained the length of from three to four inches, and is called the " May parr: " they now descend into deeper parts of the river, but remain there over the second winter. In April, the caudal, pectoral, and dorsal fins a ume a dusky margin; the lateral bars begin to be concealed by a silvery pigment; and the migratory dre , characteristic of the salmon fry or smolt, is a umed. The fish now begin to congregate in shoals, and to migrate seaward. The full-grown salmon averages a weight of between 25 lbs. and 35 lbs.; but instances are recorded of their attaining to 65 lbs., 60 lbs., 70 lbs., 74 lbs., and 83 lbs. The last-cited weight was that of a female salmon, which came into the po e ion of Mr. Groves, the fishmonger, in Bond Street, about the season of 1821; it was a short fish for the weight, but of very unusual thickne and depth. When cut up, the flesh was fine in colour, and proved of excellent quality. See Fisheries. S ALMONO IDS, Salmonidce. A family of soft-finned Abdominal fishes, of which the salmon is the type, having their upper jaw formed in the middle by the intermaxillary, and at the sides by the maxillary bones, both of which support teeth; they are also characterized by a posterior small adipose dorsal fin, and the body is covered with regular cycloid scales. They pa , by almost imperceptible gradations, into the Clupeoid or herring family, with which they have been united by M. Aga iz, to form a common group termed Halecoids. Those species of Salmonoids which, like the Clupeoids, inhabit the sea, not only approach the land, but ascend the rivers to near their source, in order to deposit their ova. SALON, or [s. 1090]