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Page:Popular Science Monthly Volume 35.djvu/384

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364
THE POPULAR SCIENCE MONTHLY.

man without their aid, and as their natural instincts impel them to bring to our very doors this great addition to our food-supply, their economic value is very great, as they put at our service a vast area of the surface of the globe which would otherwise be entirely beyond our control. The extinction of the shad would, therefore, be a national calamity.

In 1880 the fishermen believed, apparently with good reason, that the rapid decline was due to improper methods of fishing—to the erection of pounds and weirs along the shores of the salt bays and sounds, where the fishes were captured in great numbers long before they had reached their spawning-grounds. It was urged that, if these obstructions were removed, and all the shad were permitted to reach fresh water before they were captured, enough eggs would be deposited each year to keep up the supply, but that the destruction of such great numbers in salt water must necessarily result in extermination. This seemed to be good logic, but in the spring of the year 1888 more shad were caught in salt water than were caught altogether in the year 1880 in both fresh and salt water; and yet the shad-fisheries are now increasing in value from year to year, while in 1880 they were in danger of destruction.

To what is this change due? In 1880 the United States Fish Commission began systematically and upon a large scale the work of collecting the eggs from the bodies of the shad which were captured for the market in the nets of the fishermen. These eggs were artificially fertilized and hatched; the young fishes were kept for a few days in captivity in glass jars; they were then set at liberty in the fresh-water streams, and the waste of eggs was thus prevented. This work has been prosecuted steadily for eight years, and the results are briefly summarized in the following table:

 
YEARS. Shad captured in
salt or brackish
water.
Shad captured in
fresh water.
Total. Percentage of
increase over
1880.
1880 2,549,544 1,591,424 4,140,968  • •
1885 3,267,497 1,906,434 5,172,931 25
1886 3,048,768 2,485,000 5,584,368 34
1887 3,813,744 2,901,661 6,715,405 62
1888 5,010,101 2,650,373 7,660,474 85
 

The money value of the excess in 1888 over the total catch in 1880 is more than $700,000. The conditions are now more unfavorable than ever to natural reproduction, and there can be no doubt that, if no shad had been produced by man since 1880, and if all the other conditions had been as they are, the fisheries would now be valueless. The mature shad which run the gantlet of all the pounds and traps in the lower waters, and finally reach the mouths