Sutjeoti Tests to Determine tint: ixiue Factor in the Floating of Dead 

 Salmonoid Fishes, Bonneville Dam, 1945 (Continued) 



Speci- Total Placed Found Found on Time Required No, of hrs. 



men Length in Water Floating Bottom to Float Floated 



(in hours) 



6 I'll** 4j00 pm 5sOO pn 6sl5 pm 73 169 l/2 



26 July 29 July 5 August 



7 I'S** 4:00 pm 4;00 pn 2 :00 pn 120 142 



26 July 31 July 6 August 



8 I'll 1/2" 4:00 pn 3:30 pn 4:00 pm 95 l/2 192 l/2 



26 July 30 July 7 August 



9 ■ S'l* 4:00 pm 3:30 pn 2:00 pm 95 l/2 166 l/2 



.: ,1 26 July 30 July 6 August 



10 2» 4:00 pm 5:00 pm 9:00 pm 73 136 

 26 July 29 July 4 August 



(*) The blueback had been injured. A circular area 2 l/2 inches 

 in diameter from which the skin had been abraded was present 

 on the right side of the body. 



Observations similar to those in Part 1 were made on the physical 

 appearance of the specimens. Under the gross methods of observation used, 

 no difference could be noticed between the fishes of the two tests, except 

 in the single blueback. This specimen raised to the surface much more rap- 

 idly and deteriorated more quickly. Perhaps the external injury was even 

 more extensive internally and caused a more rapid decomposition. 



SUMMARY 



A total of 21 salmonoid fishes were killed and placed under observa- 

 tion to determine the length of time it took them to float, how long they 

 remained at the surface, and their external physical appearance at various 

 intervals • 



Chinook Steelhead Blueback 

 Number of specimens 15 5 I 



Number raising completely 



to the surface 14 5 1 



Average time required to 75 hrs. 91 \/Z. hrs. 48 hrs. 



float to the surface (3 days) (3 da* 19 l/2 hr») (2 days) 



Average time remaining at 152 hrs. 161 l/4 hrs. 240 l/2 hrs, 



surface (o da. 8 hrs.) (6 da, 17 l/4 hr.) (10 days) 



Variations in time remain- 

 ing at the surface 2-11 days 6-8 days 



40 



