Fish Migration 201 



even Greenland is now " nibbled " by 

 ambitious steam trawlers. Add to this 

 the pollution of our rivers and it will be 

 seen that man is his own worst enemy as 

 regards his fish supply. Legislation has 

 in recent years been brought to bear on 

 stream pollution, and in some cases the 

 mischief is not beyond all undoing. 

 Trout and many other food fishes have 

 been farmed very successfully in America 

 under government supervision. The Cali- 

 fornian Fishery authorities, for instance, 

 have enormously increased the numbers 

 of shad, a close cousin of the herring. 

 In 1871, 12,000 fry about eight days old 

 were transported from the Hudson River 

 to the Sacramento. To-day shad of re- 

 markable size have spread themselves 

 along 3,000 miles of coast from California 

 to Alaska, and over 60,000,000 shad 

 fry are annually transferred from the 

 Hudson to the Sacramento by a fishery 

 board that really deserves to be called 



