Page:Popular Science Monthly Volume 61.djvu/202

From Wikisource
Jump to: navigation, search
This page has been proofread, but needs to be validated.
196
THE POPULAR SCIENCE MONTHLY.

Sacramento pike and split-tail. Some of them, at least, are caught in the eddies formed among the cobble stones, and are held near the 'nest,' or hillock of gravel thrown up by the spawning fishes. These

 

PSM V61 D202 Sacramento salmon.png

Sacramento Salmon.

 

are covered by the sand and protected, though many are covered too deeply and are killed.

Salmon ova are about .25 inch in diameter. The 'shell' is membranous and finely porous, with a minute aperture, somewhat larger than the pores, known as the micropyle. When first extruded the ova

 

PSM V61 D202 A typical spawning stream mccloud river near baird.png

McCloud River, near Baird, a Typical Spawning Stream.

 

are soft and compressible, and it is while in this condition that they must be fertilized. Within two or three minutes after being deposited in the water they become turgid, and are then incapable of fertilization.