APPENDIX II 



1NA.R DEPARTMENT 



PortlaiK',, O:''egon District 



Office of ths Area Engineer 



Bonneville, Oregon 

 28 August 1945 



Subject? Tests to Detei-mine the Time Factor in the Floating of Dead 

 Salmonoid Fishes, Bonneville Dam, 1945 o 



To J Captain R, Bo CochranCj Resident Engineer, Bonneville, Oregon.. 



INTRODUCTION 



It is evident from weekly patrols by boat on the Columbia River 

 below Bonneville Dam, that some losses in salmonoid fishes occur either 

 at Bonneville or in its vicintiyo Daring the past years some informa- 

 tion has been gathered on the numbers of dead fish found below Bonnevillee 

 This information seems to be of very little value, other than on a cer- 

 tain date so many fish were recovered from within a certain area of the 

 river and its banko Such information does not lend itself to an analysis 

 of the fish losses occurring at Bonnc^^illeo Only after a complete study 

 of the many biological and physical factors involved will it be possible 

 to ascertain the effect, if any, which Bonneville Dam has upon fish 

 fatalities o Also it may be pointed out that only after such knowledge 

 is available can the proner remedial mepsures be takeno 



After examining many dead salmon below Bonneville, it became apparent 

 that some knowledge of the relationship betv/een the physical appearance 

 of the fish and the length of time that it had been dead would be very 

 helpful in stud;.ang the downstream drift and other factors » Even a rough 

 approximation of how -long the fish had been dead would perhaps yield some 

 olue as to where it was killed. This test to determine the time factor 

 in the floating of dead salmon is but a small part of the vrark needed to 

 be done. Additional observations upon the progressive changes in physical 

 appearance of the dead fish were made and are included in this report. 



METHODS 



Before beginning the tests, it was realized that it would be neces- 

 sary to confine the fisn in some manner, so that periodic examinations 

 could bs made. Obviously, this is not the normal conditions to which the 

 natural river losses would be subjected, but it was believed that condi- 

 tions would not be siif ficiently different to affect the results. It was 

 deoiced to confine the fish in large meshed bags and to tether them to 

 the shore o In the actual test this method proved satisfactory and the 

 alternate method of placing them in a wire cage was not usedo 



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