good condition. 



Table 9. --Lethal values of oxygen for iao: experiments using 

 several fish 



♦All fish died within 5-10 minutes of each other. 



Results . --The experiments were performed in January and February of 1951 and of 

 1952 and the fish used were therefore taken from waters ranging in temperature from 22 to 23 C. 

 The results are presented in figure 12 and table 10, the points on the graph representing the 

 average value for the two flasks in each bath. Lethal values of oxygen are seen to increase slowly 

 at first (between 20.5 and 23 C.) and then more rapidly above 26 C. In spite of considerable 

 variability in the results at each of the temperature levels, the overall trend is unmistakable. 

 The apparent rise in the lethal value of oxygen at 18 C. is, unfortunately, based on the results of 

 only two experiments and obviously a rigid interpretation cannot be given. Two things nnay be 

 noted, however; first, the temperature was at least 3 C. lower than any temperature experienced 

 by the iao in its natural environment; and secondly, the period of adjustment to this temperature 

 was probably too short. Both factors could contribute to the high lethal oxygen value obtained. 



