of salinity adaptation increased; but the temperature change from 

 25°C to 18° or 32°C was not beneficial in any respect. Between 18° 

 and 32 °C, the low temperature was more favorable for faster adapta- 

 tion with higher survival rates. 



Temperature modified the behavior in shrimp considerably. Be- 

 havior apparently altered the respiratory rates more than it did the 

 osmoregulation. The variations in behavior influenced the metabolic 

 responses differently and distorted the usual synchrony between the 

 metabolic and osmotic responses. Therefore, conclusions made on sa- 

 linity adaptation in temperatures other than normal, particularly 

 in 18°C, might be misleading. Under such conditions presumably the 

 steady-state osmotic levels would provide a more reliable evaluation 

 on the state of adaptation. 



The osmotic and chloride regulation was hyposmotic in salinities 

 above and hyperosmotic in salinities below 15°/oo. This was more or 

 less a consistent pattern throughout the test temperatures. 



At 25°C the respiratory rates varied in accordance with the 

 osmotic gradient in the test conditions and thus exhibited a positive 

 interaction between the osmotic and metabolic responses. This inter- 

 action was nevertheless absent or confined to fewer salinities in 

 18° and 32° than in 25°C. The inconsistent interaction between the 

 two physiological responses obviously did not endorse the hypothesis 

 that oxygen consumption reflected the energy expenditure involved in 

 osmotic regulation. 



Salinity and temperature requirements were shown to be size re- 

 lated in brown shrimp. As the shrimp grew to adulthood they favored 

 salinities above 10°/oo and temperatures below 25°C. In contrast, 

 the smaller juveniles (70 mm) of our previous study preferred salini- 

 ties below 17°/oo and temperatures 26° or slightly higher but not 



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