The salmon is found on the coasts of all the northern parts of the Atlantic, and in the rivers which fall into that ocean, as far s., at least, as the Loire on the European side, and the IIudson on the American. Slight differences can be noted between the American and the European salmon, but they are not generally thought sufficient to distinguish them as species. The salmon frequenting one river are, indeed, often characteristically different from those of another river of the same vicinity. The is not found in the Mediterranean nor in the Black sea, nor in any of the rivers falling into them; and in the Arctic ocean and its rivers, as well as in the northern parts of the Pacific ocean, other species of the same genus take its place. The preservation of salmon in a fresh state by means of ice, being an invention of recent times, this fish never appeared at the luxurious tables of ancient Rome except dried or salted, although its excellence was well known, the Romans having become acquainted with it in their northern conquests. Salmon is in perfection for the table only when recently taken from the water, whilst the fatty "curd" remains between the flakes of its flesh, which, 111)WeV(T, begins to disappear within 12 hours. although otherwise the fish is quite fresh. Hence the peculiarly high value formerly ascribed in London to Thames salmon.
The salmon, after its first migration to the son, passes a great port of its life in it, although under the necessity of periodically ascending rivers, in which the salmon that ascend to spawn or for other causes in autumn, often remain during most of the waiter. Salmon return, in preference, to the same rivers in which they have Passed the earliest part of their existence; as appears both from records of marked salmon, and from the characteristic differences already alluded to. Salmon ascend rivers to a great distance from the sea, as the Rhine to the Falls of Schaffhausen, and the Elbe to Bohemia. The speed with which they glide through the water in their most rapid movements is very great; it is said to be not less than 1500 ft. in a minute. or at the rate of 400 in. a day; but this, of course, is sustained only for a few moments, and the ordi nary rate of progress in ascending rivers is supposed to be from 10 to 25 m. a day. The fish, also, almost always chooses to lie for a time in some spot, waiting a fresh flood in the stream. The perpendicular height which the salmon can pass over by leaping, when there is abundance of water in the river and sufficient depth in the pool below tie fall, seems to be not more than 12 or 14 feet; they attempt higher leaps, but often fall back exhausted, or fall on adjacent rocks, where they die or are captured. They do, however, rush up steep and broken cataracts of much greater height. The ascent of
many rivers by salmon has been stopped by high weirs and other obstructions; but very simple and effectual means have been devised for preventing this by fish-stairs or fish ladders, which are often very conveniently formed by partitioning off a portion of the fall, and intersecting it from alternate sides, two-thirds of its width, by transverse steps of wood or stone, so as partially to divide it into a succession of falls. The salmon soon find out the ladder, and leap up from one step to another. By this, the interests of manufacturers and of fishery proprietors are in some measure reconciled.
As the time of spawning approaches salmon undergo considerable changes of color, besides the change of form already noticed in the snout of the male. The former brill iancy of the hues gives place to a general duskiness, approaching to blackness in the females, much tinged with red in the males; and the cheeks of the males become marked with orange stripes. Salmon in this state are "foul fish," being considered unfit for the table, and the killing of them is prohibited by British laws, notwithstanding which, however, multitudes are killed by poachers in some of the rivers, nor do those who eat them either fresh or " kippered " (i. e., dried)seem to suffer from any unwholesomeness, such as is sometimes alleged to belong to them, although they are greatly inferior in quality to salmon in other states. Salmon which have completed their spawning. con tinue for some time, at least if in fresh water, very unfit for the table. Their capture is prohibited by British laws. They are call( d "foul fish," or more distinctively, " spent fsh," or kelts; the males are also called kippers, LP being a name for the cartilaginous hook of the under jaw, and the females shedders or boggits. Such names, originally local, have become of more general use from having been introduced into acts of parlia ment. The name kelt, in particular, is now very commonly employed. When they remain for a considerable time in fresh water after spawning, kelts recover very much, and increase in weight, whereas, before spawning, there is a diminution of weight. well mended kelt" approaches in quality to a good or " clean" salmon, although far from being equal to it.
•The time of spawning is from the end of autumn to the beginning of spring, or even the beginning of summer; differing considerably in different rivers, whilst in each river it is prolonged throughout months, the elder and stronger fish of the former year prob ably ascending to spawn first. The difference of season indifferent rivers is probably to be accounted for by the temperature of the water as affected by latitude, and by the relations of the river to lakes, to low warm plains, and to snow-covered mountains.