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Page:Popular Science Monthly Volume 61.djvu/216

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POPULAR SCIENCE MONTHLY.

As spawning progresses, both sexes rapidly become emaciated. Their fins become frayed and worn, especially the caudal fin of the female, which is frequently entirely worn off. Fungus attacks the skin in various places, especially the top of the head and the fins, and it frequently destroys one or both eyes. The gills are nearly always

PSM V61 D216 Changes of the salmon alimentary canal before and after spawning.png
Alimentary Canal of a Salmon taken in Monterey Bay. Alimentary Canal of a Salmon after Spawning, taken at Battle Creek Fishery

attacked by fungus and parasitic Copepods, and half or even three fourths of the gill filaments are sometimes thus destroyed. The skin is worn off in many places, such as the side of the tail, the projecting edges of the jaws and fins, and the snout of the male. They have eaten nothing since leaving the ocean, and the alimentary canal has

PSM V61 D216 Male and female salmon after spawning.png

Male and Female after Spawning.

long since shriveled up until the stomach is scarcely one tenth its normal size; a catarrhal desquamation takes place all along the digestive tract, but especially posterior to the stomach, which portion is frequently filled with tapeworms. At least two other kinds of