showed signs of stress in 2°/ooS. They spiralled in the water and 

 occasionally swam near the surface. By 20 hours all the shrimp be- 

 came inactive with one or two deaths taking place daily for the next 

 four days. In 5°/ooS the shrimp appeared almost normal after 1-1/2 

 hours. The survivors were inactive but none buried. A maximum of 

 seven or eight shrimp buried in 36°/ooS; the number of shrimp buried 

 decreased as the salinity concentration was decreased to 25, 15, and 

 lOVooS. 



Brown shrimp tested in 18°C which were acclimated at 25 °C showed 

 relatively less stress than in 32°C. However, in individual salini- 

 ties variations occurred in the survival rates (Table 1) . Generally, 

 survival rates decreased in salinities below 15°/oo while in 25 and 

 36°/oo the rates were almost 100%. 



Brown shrimp acclimated to 18°C and tested at 25°C exhibited 

 high activity in 2 and 5°/ooS for about two hours before becoming 

 inactive. Nine shrimp were cramped in 2°/ooS within 2-1/2 hours. 

 Eight shrimp died within 24 hours and the remaining two continued 

 in a depressed state. Two shrimp cramped in 5°/ooS in two hours 

 but they were not totally paralyzed as in 2°/ooS. Mortalities in 

 this medium occurred over four days. After an initial period of 

 moderate activity, or at least less than hyperactivity, the shrimp 

 in 10, 15, 25, and 36°/ooS settled down to become normal. Again 

 relatively more shrimp, six to eight out of ten, buried in higher 

 salinities (25 and 36°/oo) as opposed to the two to five in 15°/ooS 

 and two or three in 10°/ooS. 



The shrimp acclimated to 18°C became hyperactive immediately 

 after being transferred to 2, 5, 10, and 15°/ooS at 32°C. The 

 activity continued for 1/2 hour, after which time the shrimp were 

 inactive. In 25 and 36°/ooS the shrimp were not hyperactive. In 

 2°/ooS three shrimp cramped within one hour; eight shrimp were 



5A 



