THE SMELT 



301 



catches ; the excess is immediately preserved to 

 periods of scarcity. Tlio 

 bones and scraps from can- 

 ning factories may well be 

 used in the manufacture of 

 fertilizers, for they are rich 

 in phosphorus and other im- 

 portant foods for plants. 



Fish culture. — Excessive 

 fishing has dej^leted many 

 rivers in which fish were 

 formerl.y abundant. An at- 

 tempt has been made, with 

 more or less success, to re- 

 stock such streams. Fish 

 are artificially hatched, and 

 the young (or fry) are 

 shipped to the streams need- 

 ing to be restocked. The 

 United States maintains 49 

 such fish hatcheries, which 

 in 1904 distributed 

 1,250,000,000 fish. In ad- 

 dition, many states maintain 

 independent hatcheries, so 

 that the total numl^er of 

 young annually hatched and 

 set free by all our hatcheries 

 must approach two billion. 

 Of course a large proportion 

 of these young fish are de- 



be used in 



