23 



1.10 at 0.40 ppm and 0.20 ppm. The results suggested that 

 tetrachlorocatechol caused, increased respiration rate, possibly at 

 concentrations as low as 0.1 ppm, but a consistent direct 

 relationship to tetrachlorocatechol concentration was not evident. 

 Had higher concentrations of tetrachlorocatechol been used (about 

 0.7 ppm), more positive results might have been obtained. Lack of 

 a direct relationship was probably related to differences in activity 

 of fry in the various bottles, as already discussed. Further 

 measurements of respiration rate using fry would require a 

 respirometer in which activity could be controlled in order to 

 elirainate it as a variable. 



TABLi 6 - Respiration rate of sockeye salmon fry in tetrachlorocatechol 

 (TCC); five fry per 525-ml bottle. 



Held overnight in water tefore measuring respiration rate. 



