Effect of 32°C acclimation 



The oxygen consumption of shrimp acclimated to 32°C dropped sud- 

 denly when tested in 18°C. The low respiratory rates continued 

 throughout the test period (Fig. 110a). No marked variations were 

 observed by visual examination in the respiratory rates due to 

 salinity changes. Comparison of the respiratory means did not show 

 significant changes between 5, 10, 25, and 36°/ooS. Respiratory 

 means in 2 and 15°/ooS exhibited significant differences with the 

 responses in other salinities (Table 17). 



The shrimp acclimated to 32° and tested in 25 °C maintained a low 

 initial respiratory rate in 15°/ooS and high rates in 2 and 36°/ooS 

 (Fig, 110b). These responses were similar to those of shrimp accli- 

 mated and tested in 25°C under the same salinity conditions. In 

 36°/ooS the respiratory rates were maintained at the initial high 

 level while in 2 and 5°/ooS the rates dropped during the successive 

 time intervals. Consequently the animals in 36°/ooS showed signifi- 

 cant differences with the rates in other salinities. At the same 

 time the shrimp in 15°/ooS did not show significant changes with 

 those in 2, 5, 10, or 25°/ooS (Table 17). It was not known to what 

 extent the decreased oxygen uptake in 2 and 5°/ooS represented a 

 state of depression. 



The shrimp acclimated and tested in 32°C used the lowest amount 

 of oxygen in 36°/ooS and a lower amount in 15°/ooS than in the other 

 salinities (Fig. 110c). In these respects the respiratory rates 

 were different from the shrimp acclimated to 25°C and tested at 32°C 

 (Fig. 109c). The respiratory rates in 15°/ooS showed significant 

 differences (P=0.01) with the responses in 25 and 36°/ooS but not in 

 2 or 10°/ooS. Also the shrimp in 10°/ooS responded like those in 5 

 and in 25°/ooS (Table 17). In 36°/ooS the oxygen consumption rates 

 differed significantly from the rest of the salinities except in 



^ / o oo • 



232 



