244 ECONOMIC ZOOLOGY AND ENTOMOLOGY 



This is nature's way, and it is a wasteful one, yet enough fish 

 were produced each year to maintain the species in great 

 numbers. But when the demand of man for fish became so 

 great that, hundreds, and later, thousands of men devoted 

 their time and energies to catching salmon wherever possible, 

 it was found that the number of fish was fast decreasing. 

 Under these conditions, the government established hatcheries 

 along some of the rivers where the salmon naturally spawned. 



On these spawning beds the salmon are taken by means of 

 traps or nets, and, if the eggs are ripe, the body of the female 

 is held over a pan and gently pressed so the eggs will flow 

 out into the water in the pan. The milt from the male is 

 procured in the same way, and is poured over the eggs, thus 

 fertilizing them. The eggs are then taken to the hatchery, 

 where they are placed in wire baskets which are lowered into 

 troughs of flowing water and kept until the young fish hatch 

 and have absorbed the yolk sac and are able to take care of 

 themselves. In this way 80 per cent, to 95 per cent, of the 

 eggs that are taken are saved, and millions of young fish are 

 turned into the streams from the hatcheries that are located 

 along the tributaries of many of the most important 

 salmon rivers. 



This is surely a great improvement over nature's wasteful 

 methods. In this way the fisheries on the Sacramento and 

 Columbia rivers have been maintained, whereas otherwise they 

 would have long ago been depleted. Other salmon hatcheries 

 have been established in Washington, British Columbia and 

 Alaska, until now provision is made for caring for the eggs 

 of all of the species of salmon, especial attention being paid 

 to the king, or chinook, and the red, or sockeye, salmon, as 

 these are commercially the most important 



In the same way the eggs of many species of trout are taken 

 and hatched, and the young turned directly into streams or 

 lakes, or kept in ponds where they can be fed and reared. 

 At certain stages of their development the eggs can be packed 

 and shipped long distances, or the young may be carried shorter 

 distances in cans if the water is kept well aerated. Thus many 

 barren streams and lakes can be stocked with choice varieties of 



