consumption of shrimp tested at 25°C between 15°/ooS and the other 

 media (Table 16); but the respiratory rates in 2, 5, and 36°/ooS did 

 not vary significantly from each other as did the rates between 

 10°/oo and 25°/ooS, The oxygen consumption increased with the devia- 

 tion of the test salinities from 15°/ooS. The corresponding varia- 

 tions in the blood osmoconcentration would suggest the presence of a 

 possible interaction between the ionic and respiratory rates. However, 

 this relationship was not found consistently in other test conditions. 



Tlie respiratory rates at 32°C increased to highest levels of all 

 test temperatures (Fig. 109c) . Oxygen consumption rates were ini- 

 tially highest in 15 and 25°/ooS. In 2 and 5°/ooS the rates were low 

 while in 10 and 36°/ooS they were median. Some important differences 

 were noticed in the salinity-related responses between the test tem- 

 peratures 25° and 32°C. Comparison of the respiratory means at 32°C 

 indicated that oxygen consumption occurred at the same rate between 

 2 and 5°/ooS, 10 and 36°/ooS, and 15 and 25°/ooS. Significant dif- 

 ferences (P=0.01) were found in other comparisons (Table 16). There 

 was a high mortality in 2°/ooS. The low respiratory rates in this 

 concentration may perhaps indicate a state of depression. 



At 18°C the oxygen consumption rates decreased to the lowest 

 levels of all test temperatures (Fig. 109a). In 2°/ooS the experi- 

 mental shrimp died within four hours. The respiratory rates in 

 36°/ooS dropped to a low level like those in 15°/ooS. With the ex- 

 ception of these two salinities the respiratory pattern in other 

 salinities was similar to that of animals acclimated to 25°C. Com- 

 parison of the oxygen consumption means between 2 and 5°/ooS, 10 and 

 25°/ooS, and 15 and 36°/ooS did not show significant variations (Table 

 16). However, in other salinity combinations the comparisons were 

 significantly different (P=0.01). 



230 



