146 



Scientific Proceedings (76). 



sential factor connected with the scorbutic condition. This 

 should be borne in mind, and the results of experiments on growth 

 should not be considered as directly transferable to infantile 

 scurvy or similar dietary diseases. 



81 (1145) 



Oxygen utilization by fishes and other aquatic animals. 1 



By Geo. G. Scott. 



[From the United States Fisheries Biological Station, Woods 



Hole, Mass.] 



A . Lowering of the temperature causes a reduction in the rate 

 of oxygen consumption. In one case, while one lot of fishes 

 consumed 78 per cent, of the available oxygen supplied at 12" C; 

 a similar lot of fishes in water 4 0 colder consumed but 60 per cent. 

 In a second case, a fish in water at 20° C. consumed 94 per cent, 

 of the oxygen present while a similar fish at 3 0 C. consumed but 

 57 per cent. Breathing had ceased in this case but was resumed 

 on return to warmer water. 



B. It was noted that oxygen was consumed more rapidly in 

 tall, narrow vessels of water than in broad shallow ones. Fishes 

 moving about in shallow vessels of water tend to reaerate the 

 same. In one experiment to test this, one lot of fishes in tall 

 narrow vessels of water consumed 80 per cent, of the oxygen 

 supply, while in the broad shallow water at the end of the same 

 period, the analysis indicated a reduction of but 20 per cent, of 

 the original oxygen supply. 



C. Fishes kept in dark vessels apparently consume oxygen at 

 a less rapid rate than those exposed to light. Thus in the light 

 one fish consumed oxygen at the rate of 0.12 c.c. per gm. per hr. 

 while in the dark the rate was D. 11 c.c. per gm. per hr. But 

 there was no evidence as to rate of oxygen consumption being 

 less at night than in the daytime the rate being approximately the 

 same. 



D. Some forms show more resistance to low oxygen supply 



1 Published by permission of the Commissioner of Fisheries. 



