Table 3« TT'om'bor of chinook salmon examined at the Bonneville 



Hatchery (approximately one mile below Bonneville Dam) 

 and riLimber of injured fish observed* during th.e period 

 September 25-30, 1946o 



* In addition tr the injuries noted in the table, 12 fish or 2.4 percent 

 had open body woundK. 



It Hiay be pointed out that of the total of 510 f ieh examined on 

 September 25 and September 30, 26.9 percent had dorsal-fin injuries 

 (Figure 3), 19.5 percent had ventral<=fin injuries (Figure 4), and 3o? 

 percent had well-defined encircling abrasions (Figure 4). 



Of the 134 fish with dorsal-fin abrasions, 82.8 percent had the 

 acsompanying ventral-fin injury. All of the fish with encircling abra- 

 tions had both dorsal=and ventral^fin injuries. 



Other injuries to fish observed at Bonneville Hatchery in the 

 sample of 510 examined on September 25 and September 30 show&d 2.4 per= 

 cent had open wounds about the body. Several of these fish had jres cent- 

 shaped cuts on the underside of the body between the pectoral fins very 

 similar to many of the injuries observed at Big White Salmon Hatchery, 

 No explanation is available as to the cause of such injuries. 



In September 1945, Robert R. Rucker of the Service made observations 



of injured fish above and below Bonneville Dam. The following quotation 



is taken from his monthly report of activities. Complete text of hi.-s 

 observations is given in the Appendix* 



••On September 15, the gill-net oaught ohinook salmon from 

 imriediately belov/ and above Bonneville Dam were examined. It 

 was desired to determine whether or not the fish taken above 

 the dajtri showed a greater percent with injuries on the dor-:ai 

 fins. Of 170 chinook salmon taken below the Dam, 19^ showed an 

 injury on the dorsal fins of 100 chinook salmon takeii above the 

 Dam, 13^ showed an injury on the dorsal fin. These data indi- 

 cate that the dorsal-fin injtiry is probably not incurred by the 

 fish in the fishways at Bonneville Dam." 



Observations of Fish Passing Through Submerged Openj-ngs in Bonnevill e 

 Fish Ladder© Preliminary to the study of salmon mortality of the Colorribia 

 River in the vicinity of Bonneville Dam, a conference was held between 

 personnel of the Fish and Wildlife Service and representatives of the 

 Corps of Engineers at Bonneville. It was decided that it would be desirable 



