Page:Popular Science Monthly Volume 20.djvu/46

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36
THE POPULAR SCIENCE MONTHLY.

Theoretically, then, the dredging would—1. Extend the beds; 2. Destroy their fecundity by removing the brood-oysters and by destroying their progeny. Practically, has this been the case?

In the absence of previous surveys of the beds, the testimony of the fishermen must be accepted with regard to the extension of area, and the testimony was unanimous to that effect, some of the beds having doubled in size during the last thirty years. The testimony was also to the effect that all the beds in question had materially deteriorated, the general opinion being that, with the improved appliances now in use, there could have been taken twenty-five years ago from two to seven times as many oysters as at present! But we are not compelled to rely solely upon these statements. A comparison of the results obtained from an investigation of newly discovered beds in the Chesapeake Bay with those beds in the sounds that had long been subjected to the dredging influence shows marked differences, and affords more certain methods of proving the deterioration of old beds. In 1879 areas were discovered in the bay upon which oysters existed, and the locality of which was known to but few of the fishermen; the beds were thus practically in a natural state. The following differences were observed between them and the beds in the sounds: On the new beds in the bay the oysters were generally found in clusters of from three or four to twelve and fifteen; the shells were clean and white, and free from worms; the spaces between the larger oysters were filled with the young growth and barnacles; usually the clusters had a large tuft of red sponge attached to them, and sponges were very plentiful over the beds; the mature oysters were long and narrow, with the lower valve very deep and bills very thin and sharp; the animal itself was much larger and thinner than those of the same age on the worked beds in the sounds; and this last difference is probably due to the difference of water and to the fact that, growing as they do in clusters, food is not so readily obtained. The oysters taken from a bed which has been worked for some time are usually single or in clusters of two or three; they are larger than the corresponding class on the unworked beds—that is, broader in comparison to their length and of greater thickness; the valves are blunt and thick about the lips; and the animal fatter and thicker than those of the same age in the new beds. The shells are dirty, with much mud or sand clinging to them. There is but little sponge attached to the shells; but they are covered with worms, and bored in many places by the boring pholad; and the older the bed and oysters, the larger the number of worms and the less healthy is the appearance of the shell.

The new beds were hard, and the clusters seemed more firmly attached to the bottom, and required greater force to detach them than was necessary on the beds in the sounds. There was comparatively but a small number of broken shells, and the bottom was usually too hard to be penetrated by an iron probe. The beds in the sounds were