292 



PRACTICAL ZOOLOGY 



ing about eighteen pounds, but occasionally attaining a weight 

 of over one hundred pounds. Lake trout are captured usually 

 in gill nets. They are omnivorous, but show special preference 

 for lake herring. The spawning season ranges from September 



FIG. 174. Pike perch. (From U. S. Fish Manual.) 



to November, according to the latitude. Millions of eggs are 

 cared for and distributed by the government each year. 



The wall-eyed pike or pike perch (Fig. 174) is another well- 

 known and valuable species. It is common in the Great Lakes 

 region and is extensively propagated by the Bureau of Fisheries. 



FIG. 175. Salmon. (From U. S. Fish Manual.) 



The Canning of Salmon. Quite a number of species of 

 salmon are used for purposes of canning, especially on the Pacific 

 coast. " The canning of salmon, that is, the packing of the 



