SubjBct; Tests to Dotermin© the Time Factor in the Ploating of Dead 

 Salmonoid Fishes, Bonneville Dam, 1945 (Continued) 



On 21 July observations were made on the appearance of the fish float- 

 ing on the surface. The fish lay on their sides in the water, with the 

 belly slif,htly higher than the back. The abdominal cavity was well dis- 

 tended with gas, appearing puffed out posteriorly. The paired fins ex- 

 tended straight out from the sides of the body, evidently forced into that 

 position by the pressure of gas inside the body. The surface of the skin 

 was soft and dull, and the flesh soft and spongy. There were no marks or 

 broken skin on the body. A strong and definite odor of decaying fish was 

 present. The fish were again checked on the morning of 23 July; the side 

 of the fish floating upward had turned brown (sunburnt) from exposure to 

 the sun and air. The skin was leathery and wrinkled, and cracked when the 

 fish was bent. The head and tail regions were beginning to develop a fungus 

 growth. External evidence of bodily deterioration was beginning to show at 

 base of anal fin and around anal opening. The skin had burst and the flesh 

 beneath was exposed. The fins were becoming frayed and torn. The body was 

 limp and the flesh soft and pulpy. A very strong odor was present. 



From this time on, until the fish finally sank, their condition became 

 progressively worse. It would be very difficult, if not impossible, to 

 even approximately define their physical appearance at any definite time, 

 during this period, since it was characterized by the continued growth of 

 fungus on the body and the rapid deterioration of the entire fish. Evi- 

 dently the internal structxu"es were entirely decomposed for the fish floated 

 as limply as a rag in the water. It seemed evident that the fish was held 

 together by the skin. By the time they were ready to sink, only a slight 

 agitetion was needed to Isrealc them up» 



Part 2 



fhe second test was made partly to confirm the results of the first 

 test, and to see if there were any great difference in other species. In 

 the following table, specimens 1 to 4 are chinook, specimen 5 a blueback, 

 and specimens 6 to 10 steelhead. ~ 



Speci- 

 men 



5* 



Placed 

 in Water 



2 lOO pm 

 26 July 



2 :00 pm 

 26 July 



2 :00 pm 

 26 July 



3 ;15 pm 

 26 July 



1«9 1/2" 3:15 pm 

 26 July 



Total 

 Length 



1»10" 



2'1» 



I'S* 



Found 

 Floating 



5:00 pm 

 29 July 



5:00 pm 

 29 July 



5:00 pm 

 29 July 



5:00 pm 

 29 July 



3:30 pm 

 28 July 



Found on 

 Bottom 



4:00 pm 

 31 July 



6:15 pm 



5 August 



2:00 pm 



6 Augus t 



4:00 pm 

 31 July 



4:00 pm 



7 August 



Time Required No. of hrs . 

 to Float Floated 



(in hours) 



75 47 



75 



75 



73 3/4 



48 



169 1/4 



189 



47 



240 1/2 



39 



