FISHES 



141 



are caught when the eggs are ripe and the eggs are gently 

 squeezed from the ovaries into the water (Fig. 105). Then 

 some of the spermrcells are similarly squeezed from the male 

 fish and mixed with the eggs. This provides for fertilizing 

 most of the eggs, which would probably not occur in nature. 

 Special apparatus is devised for keeping the eggs supplied 

 with fresh water until they hatch (Fig. 106). When the 



Fig. 106. — Interior of fish hatchery. 



young are old enough they are fed for a time, then the young 

 fry, are set free in the waters where more fish are desired. 

 Millions of young fish are every year distributed by the 

 government all over the United States to be placed in ponds, 

 rivers, and lakes where the supply is deficient, or in the ocean 

 along the shore. 



106. Economic importance of fishes. — From very ancient 

 times fishes have formed a considerable part of the food of 

 peoples that lived near bodies of water. The importance to 



