250 ECONOMIC ZOOLOGY AND ENTOMOLOGY 



each female yielding usually about 30,000 eggs, but some have 

 been known to produce two or three or even five times as many. 



Although the menhaden (genus Brevoortia) are but little 

 valued for food, they are of great commercial importance 

 on account of the oil that is extracted from them. The refuse 

 is used for fertilizer. They are also largely used in the prepa- 

 ration of fish meal for domestic animals. 



The anchovies, family Engraulidce, are fine-flavored oily 

 little fish that are often preserved in oil or spices. They are 

 very abundant in many waters, and form an important source 

 of bait and of food for other fishes. 



In many respects the family Salmonida, including the salmon, 

 trout, and whitefish, is the most important of all. The 

 salmon fisheries constitute one of the principal industries of 

 the Pacific northwest, the whitefish are among the most 

 important fish of the Lake regions, and the trout are found 

 in almost all swift-flowing streams and clear cold lakes, and 

 are more sought after by the angler than any other fish. 



The Pacific salmon, genus Oncorhynchus, occur in the north 

 Pacific. Little is known of their habits while in the sea, 

 but just before spawning time they enter certain rivers and 

 start upstream for the spawning grounds, taking no food 

 while in fresh water. The king salmon, or quinnat salmon, 

 enters, in enormous numbers, such rivers as the Sacramento, 

 Columbia, Frazer and Yukon, large streams fed by mountain 

 snows. Up these rivers they may make their way through 

 rapids and over falls for several hundred miles, often to the 

 very head waters, before spawning. In the Yukon they may 

 ascend 2250 miles from the ocean. 



The red salmon, or sock eye salmon, is commercially the most 

 important of all. They are taken in large seines or traps in 

 Puget Sound or similar bays while going in great schools to 

 the rivers which they ascend to reach their spawning grounds. 

 They will enter only such rivers as are fed by lakes, and spawn 

 in the small streams that flow into the lakes, sometimes 1000 

 to 1800 miles from the ocean. The other species spawn closer 

 to the sea in almost any fresh water stream. After spawning, 

 the salmon remain near their eggs until, too weak to resist 



