Page:Popular Science Monthly Volume 4.djvu/39

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29
THE GROWTH OF SALMON.

journ in fresh waters, it ascends the river, its roe or spawn developing as it ascends; till, about Christmas-time, or sometimes earlier, it reaches the shallow head-streams of the river, in the gravelly beds of which it deposits its eggs, returning immediately afterward to the sea, no longer in the bright, plump, muscular condition in which it ascended, but a lean, lank, ugly, wounded beast, which one would hardly recognize as Salmo salar. Fig. 5 represents the head of a "kelt," as those salmon are called which have newly spawned. The curved projection, or hook, on the lower. jaw, is a cartilaginous membrane, the use of which nobody knows. The fish is in a very weakly condition, as his fat is gone, and he perhaps assumes this appearance to frighten other animals, which might otherwise be tempted to attack him. The drawing is taken from the photograph of a salmon, weighing twenty pounds, which was found dead on the banks of one of our Welsh rivers.

Fig. 4.
PSM V04 D039 Six week old salmon.jpg
Young Salmon Six Weeks old.
a, b, c, size of salmon at two, three, and four months respectively.

This fish, had it survived, would have returned to sea, recovered its fat, and presently come back worth £2 or £3, whereas, by dying in this condition, it was worth nothing. It had, however, done its duty by depositing perhaps 16,000 eggs. Only a very small percent-age, however, of the eggs laid ever become adult fish. Floods wash them out of their gravel nests; ducks, and other birds, eat them; beetles and various insects attack them; they are smothered with mud, or left high and dry on the shore; the young fish are poisoned by pollutions, or diverted into mill-leats and canals, and so lost; trout eat them wholesale; in fact, the whole of their earliest existence is a very living death, and it is a wonder, with all the ordeals they have to pass through, that we have any salmon left. To kill them legitimately for food for ourselves is bad enough, and we ought to do all we can to protect them when young.

In the artificial system of breeding salmon the adult fish are caught just as they are on the spawning-beds, and the eggs taken from them; the ova and milt are properly mixed together, and the eggs placed in