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Page:Popular Science Monthly Volume 56.djvu/249

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235
EASTERN OYSTER CULTURE IN OREGON.

States Fish Commission during the summers of 1897 and 1898, among other things resorted to the artificial fertilization of the eggs in a temporary laboratory, carrying the delicate embryos to the swimming stage and dumping them by thousands into the bay. Given some clean crocks, a microscope, dissecting instruments, tumblers, rubber tubing, thermometers, and instruments to test the saltness of the water, and innumerable embryos can be cared for without much trouble. The process, as practiced by Brooks, Ryder, Nelson, and others in America, is too well known to need repeating here. Its efficacy is well established, and, in spite of the incredulity of the oystermen, who wished to see the oysters spawn "spontaneous," as they expressed it, an incredulity amounting almost to opposition, the writer has persevered in this work for two seasons and intends to continue it the coming summer.

The native oyster of this Northwest coast (Ostrea lurida), smaller and by many preferred to its Eastern congener, while it is far less fruitful in its spawning than the latter, retains its young within the parent shell until long after they have passed the tender stages, when they leave the mantle cavity of the parent to swim for themselves. This oyster could rightly be called viviparous, while the Eastern oyster is oviparous. On account of its nurse-acting proclivities

PSM V56 D0249 An experimental spawning float.png
An Experimental Spawning Float.

this West-coast oyster has an immense advantage here over the introduced species. The latter's eggs have to run the following gantlet: (1) Not meeting with a fertilizing cell and perishing in consequence; (2) sinking, before or after fertilization, in the fatal mud; (3) being eaten by small fish and other minute animals;