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Page:Popular Science Monthly Volume 35.djvu/385

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THE ARTIFICIAL PROPAGATION OF SEA-FISHES.

of the rivers, are excluded by dams and other obstructions from all the streams which are of most value as feeding-grounds for the young; and the area which is now available for spawning is restricted to the lower waters of the rivers, which are so assiduously swept by drift-nets and seines that each fish is surely captured soon after its arrival, and before it has had an opportunity to deposit its eggs. The number of eggs which are naturally deposited is now very small indeed, for, while the take upon the spawning-grounds has increased from 1,600,000 in 1880 to 3,600,000 in 1888, the take in salt water has increased from 2,500,000 to 5,000,000, and the shores of our bays and sounds are now so thoroughly lined with both nets and pounds that the number of shad which reach the spawning-grounds at all is proportionately much less than it was eight years ago, and more shad are now taken each year in salt water, where spawning is impossible, than were taken altogether in 1880. The fact that, in spite of all this, the value of the fisheries has increased eighty-five per cent, seems to prove that the shad is now entirely an artificial product, like the crops of grain which are harvested on our farms.

If any one doubts whether this result is due to man's efforts, we have more conclusive evidence. Previously to 1870 no shad were found in the Pacific Ocean or in any of its tributaries. Between 1870 and 1875 the United States Fish Commission introduced a few young shad into the Sacramento River. The number was very small, but the little fishes made their way down to the Pacific to feed and grow large and fat, and to return at last to the fresh water to reproduce their kind. Some of them came back to the same river, but others, following the warm Pacific current, wandered farther north into other rivers, until now the shad is in some places sufficiently abundant to furnish profitable fisheries, and it is distributed along more than three thousand miles of the Pacific coast of North America, and is still spreading northward in such a way as to indicate that it will in a few years be found in the rivers of Asia, so that the descendants of the shad of the Chesapeake Bay will increase the food-supply of China. If such noteworthy and valuable results follow the artificial culture of a fish which spends the greater part of its life in the ocean, and there obtains its food, is there any reason why man should not also make good his destruction of species which are more strictly marine?

The great increase in the shad-fisheries during the last eight years has been effected by the use of means which, while effective, are very crude and primitive as compared with those of modern agriculture, for example, and we must look for great improvements and a vastly greater return in the future. A farmer who did nothing more than to save and sow wild seeds which would