Table 1. Nxjmbor of bluebaok and chinook salmon and steelhead 

 trout counted, number of fish in various samples 

 taken, and number of injured fish observed in each 

 sample at Bonneville Dam during June, July, and 

 August 1946. 



s Total 

 Date ; count 



, A* 

 "Number 



: in 

 ssample 



Number w/ 



encircling 



abrasions 



B 



X 



Percent 



C* 

 Number 



in 

 sample 



Number w/ ; D 

 other i "C 



injuries jPercent 



1946 



STEELHRA.D TROUT 



June 3,265 1,466 



July 2Q,559 11,782 

 August 58,356 46,747 



June 



7,805 



3,290 

 64,704 46,605 

 August 1,746 797 



July 



June 30,051 24,099 

 July 20,960 13,042 

 August 45,421 28,403 



1,02 3 

 718 



2,463 



197 

 594 



478 

 38 



973 



,545 

 978 



1,9 

 1.2 



1.1 

 4.6 



5.9 



8.7 

 3.6 



♦These numbers represent the sum of the samples counted each day. 



The study at the two hatcheries was concerned with fall-riin fish 

 which did live until spawning time in the hatcheries j therefore, injuries 

 such as cut or mutilated dorsals and ventrals and encircling abrasions 

 did not cause the premature death of these fish. Such injuries to spring- 

 run fish that must remain several months longer in waters of the upper 

 tributaries before reaching sexual maturity might cause a high mortality 

 because of fungus or other infections. 



Big White Salmon Hatchery . At this hatchery, salmon ascend a small 

 fish ladder, enter a long concrete pool, and remain several days to com- 

 plete development of their eggs and sperm. From here the males and females 

 are sorted and placed in separate holding areas in an adjacent pool. There 

 are no nets used in these operations, and consequently observers believed 

 it impossible for the fish to get dorsal or ventral fin injuries or en- 

 circling abrasions in either the fish ladder or the hatchery pools. The 

 number of fish examined at the Big White Salmon Hatchery and the number of 

 injured fish obeerved are presented in Table 2. 



