APRIL 59 



the front of this great wave comes the little 

 alewife usually known in our eastern fish 

 markets as the herring. These fish are very 

 closely followed, indeed their run is over- 

 lapped, by that of the shad. This finest 

 of the marketed fresh fish of the eastern 

 United States is succeeded by the oily men- 

 hadden. 



WHY FISH ASCEND RIVERS 



Such fish as leave their home in the sea 

 and take their long journey up the rivers 

 to lay their eggs are known to fish students 

 as anadromous or "up-running" fish. We 

 used to say of fish having this peculiar 

 habit that they had originally been inhabi- 

 tants of the fresh water, and that genera- 

 tions ago they had taken to the ocean as a 

 better feeding ground. The changed life ' 

 we thought had not gone on long enough 

 for their entire adaptation to the new condi- 

 tions, and that the fish came up the river 

 in order that their young might find, in the 

 tender period of life, the ancestral condi- 

 tions to which their inherited constitutions 



