dead within 24 hours and the ninth after 72 hours. Slight cramping 

 was also noticed in 36°/ooS among two out of the ten shrimp, both of 

 which died within 15 minutes. The others were normal. After the in- 

 activity the animals in 10, 15, and 25°/ooS became normal. 



Transfer from the 32 °C to 25 °C did not affect the behavior or 

 survival to any great extent in any of the salinities except 2°/oo. 

 In 2''/ooS the shrimp were hyperactive for 2-1/2 hours before becoming 

 quiet. Mortalities in 2°/ooS occurred on the second and third days. 

 In 5°/ooS there was immediate activity for one hour and then normal 

 activity for the remaining days. One shrimp died on the third day. In 

 10 and 15°/ooS, half the shrimp buried immediately while the others 

 showed normal activity. In 25 and 36°/ooS the shrimp were initially 

 active for ten to fifteen minutes but then became less active. After 

 the second day most of the shrimp buried. 



Brown shrimp tested at 18°C from 32 °C acclimation were heavily 

 stressed in the extreme test salinities 2, 5, and 36°/oo. The shrimp 

 were inactive from the beginning in all salinities and remained so 

 throughout the testing. Any activity was exhibited generally by 

 stressed animals only. In 2°/ooS, half the shrimp were slightly 

 cramped by three hours; all shrimp were dead in this salinity within 

 20 hours. Most mortalities in the other salinities occurred on the 

 third and fourth days of testing. Some shrimp buried in 5, 10, 15, 

 and 25°/ooS but none in 36°/ooS. 



In summary three distinct phases could be recognized in the be- 

 havior of shrimp. The immediate response was hyperactivity or mod- 

 erate activity. This was followed either by a temporary inactive 

 phase and later normal activity and recovery, or else by depression 

 and death. The shrimp from 25°C were highly sensitive as reflected 

 in their activity patterns to both salinity and temperature changes, 

 more so than those acclimated to and tested at 18° or 32°C. The 



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