Man and Nature 



429 



increase, due probably to increased facilities for taking and 

 preserving the catch. 



The survival of the salmon in the face of so great difficulties 

 is undoubtedly due in large measure to the extensive propa- 

 gation carried on mainly by the government, but also by state 

 and private concerns. \ 



From California to Alaska the Bureau of Fisheries main- 

 tains salmon hatcheries, which annually distribute in our 

 waters some 200,000,000 eggs, fry and older fish. Since the 

 start of propagation work in 1872 to the end of 1921 a total 

 of about 4,000,000,000 salmon eggs have been hatched and 

 "planted" in Pacific waters, besides those which have been 

 sent to the Atlantic Coast and to foreign countries. The 

 hatcheries are located on some salmon stream, where there 



TRAY OF SALMON EGGS 

 Courtesy of the U. S. Bureau of Fisheries. 



is an abundant supply of good water and plenty of fish from 

 which to strip the eggs. The fish are caught on their way 

 to the spawning grounds, either by seining them from the 

 river, or in a trap, and if not "ripe" (i. e. ready to shed their 

 sperm and eggs) they are retained in a pound or enclosure 

 until the proper time. In obtaining the eggs two methods are 

 employed, either the living fish is "stripped" of her eggs, 

 or she is killed, opened and the eggs removed. The latter 

 method causes no loss of fish as might appear at first sight, 

 since the fish die after spawning in any case; and is more 

 efficient than the former, since all of the eggs are obtained, 

 which is not the case in "stripping." In "stripping" the 

 female, she is held in the hand or placed in a special frame 

 for this purpose, while the "stripper" runs his thumb down 

 her belly and squeezes out the eggs into a pail. The sperm 

 or "milt" of the male is obtained in the same way. After 



