The zero hour reading in Fig. 121 represents the metabolic rates of 

 brown shrimp in natural sea water of 15°/ooS and 25°C. 



The control animals (those tested at 25°C, 15°/ooS) maintained 

 a steady metabolic state at a level slightly lower than 0.2 mlO_/L/g 

 (Fig. 121). The new steady-state level was established in about six 

 hours after an initial increase in the respiratory rate. This ini- 

 tial increase might have occurred in response to the introduction of 

 synthetic seawater into the respiratory chamber replacing the 

 original salt water control. 



The initial increase in the oxygen uptake at 32 °C was greater 

 than the increase in 25°C. Also, the steady-state metabolic level 

 at 32°C, established at about six hours, was higher than in 25°C. 

 At 18 °C there was a gradual drop in the oxygen consumption during 

 the immediate response phase from the control level 0.19 mlO„/L/g. 

 After four hours, the new respiratory steady state was established 

 at 18°C well below the control level. 



During the stabilization process uniformly high individual 

 metabolic variations occurred between one and four hours through- 

 out the test temperature range (Ref . standard deviation values) . 

 Although the tests were made in 15°/ooS synthetic seawater, sta- 

 bilization and new steady-state levels occurred much the same as 

 in natural seawater of the same concentration. Survival of the 

 test animals was low at 32°C. 



Oxygen consumption in reduced calcium 



The effect of 25% Ca on the respiratory rates of shrimp was 

 studied at 18°, 25°, and 32°C (Fig. 122). 



The respiratory pattern in 25% Ca concentration varied from the 

 control shrimp in two respects. The immediate responses at 25° and 



267 



