172 The Pacific Salmon 



It is not often possible to gage the effects of 

 fish-cultural work in public waters, and this is 

 especially true of the Pacific salmons. Some 

 light has, however, been thrown on this subject 

 by the marking of young salmon prior to their 

 release in the open waters ; thus, at the hatchery 

 on the Clackamas River, Oregon, one lot of five 

 thousand fingerling salmon was liberated in 1896 

 after having the adipose dorsal fins cleanly shaved 

 off with a razor. So many of these fish were 

 subsequently captured as mature individuals as to 

 indicate that an unexpectedly large proportion of 

 young salmon turned out by the hatcheries sur- 

 vive and return to the rivers. Between four and 

 five hundred of the fish so marked are known to 

 have been recaptured, the minimum weight of 

 which was not less than ten thousand pounds. 

 These figures indicate that for every thousand fry 

 liberated, two thousand pounds of adult fish were 

 caught for market. The cost of producing and 

 planting young salmon at the government hatch- 

 eries does not exceed one dollar per thousand, 

 and the value of the fish resulting therefrom 

 caught for market is at least ^100, or five cents 

 per pound. 



The possibility of acclimatizing the Pacific 



