survival of shrimp. However, two shrimp died in 5°/ooS after ex- 

 periencing an initial stress in 85% Na concentration. In 10°/ooS 

 one shrimp died in 120% Na after molting. 



Effect of reduced potassium 



In 5°/ooS the initial behavior in 40% and 60% K media was similar 

 to the control shrimp. Seven hours later two shrimp in 40% K started 

 experiencing stress and both died in about 23 hours. In 60% K one 

 shrimp died. In 10°/ooS the shrimp developed stress earlier and in 

 greater numbers. As a result of the stress, six shrimp out of ten 

 died in 40% K medium. In 50% K one shrimp died by 11 hours and the 

 others were depressed. In 60% K one shrimp died by 22 hours but it 

 was not stressed until after 11 hours. 



Effect of reduced calcium 



The lethal concentration levels of 5% and 10% Ca were not used 

 in these studies. At 5°/ooS containing 15% Ca the shrimp apparently 

 behaved similar to the control shrimp. However, one animal was 

 stressed after 11 hours and died in 22 hours. The shrimp were very 

 quiet in 10°/ooS with 15% Ca concentration. One animal was stressed 

 and one died by 11 hours. By 23 hours the stressed animal died and 

 another became stressed. In 25% Ca the animals were active and 

 appeared normal. 



Effect of reduced magnesium 



The shrimp in 5°/ooS with 0% Mg were initially active. After one 

 hour one animal became cramped and died by 11 hours. Later two more 

 shrimp were under stress until they died by 22 and 23 hours. The 

 surviving shrimp were inactive and some of them were undergoing 

 stress by the time the studies ended. In 10°/ooS with 0% Mg half 

 of the shrimp died by 22 hours. Three more died by 25 hours. In 

 the 3% Mg medium survival rates improved. The only shrimp that was 

 dead by 25 hours had shown signs of stress after 23 hours. At that 



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