Behavior 



The behavior and survival rates of brovm shrimp in each of the 

 test conditions mentioned previously were monitored for one week. 

 Ten-gallon aquaria with undergravel filters and sand substrates were 

 used for the observations at 25° and 32 °C; the tanks were set in a 

 water bath to maintain the high temperature. Thermostatic aquaria 

 of 50-gallon capacity were used for testing at 18°C. They also had 

 undergravel filtration and sand substrates. A partition was inserted 

 in these tanks so that the shrimp were actually held in 25 gallons 

 of seawater. Ten shrimp (average length 94.4 mm and average weight 

 6.4 g) were tested in each experimental condition. They had been 

 exposed to the control (25°C, 15°/ooS) or to one of the acclimation 

 conditions (18° or 32°C, 15°/oo) as previously described. The shrimp 

 were directly transferred and were not fed for the duration of test- 

 ing. Timers on the light switches were set to give 12 hours each of 

 alternate light and darkness. Observations of behavior were contin- 

 uous for the first few hours after transfer and were made every four 

 hours, excluding the nighttime, after the second day. Mortalities 

 were removed as they occurred. Those shrimp which molted in the test 

 aquaria and were attacked and killed by other shrimp in the same tank 

 were not counted as deaths due to the salinity and/or temperature 

 change unless they had shown signs of distress before molting. 



Behavior in Media of Deviated Ion Ratios 



Behavior and survival of brown shrimp exposed to media of de- 

 viated ionic ratios were studied in two series of tests. In the first 

 series shrimp were acclimated to artificial seawater with the normal 

 proportion of all cations and then tested in seawater with deviated 

 ion ratios. In the second series the shrimp were acclimated to de- 

 viated ion media and then tested in extreme salinity concentrations 

 with normal ion ratios at extreme temperatures. For both series the 



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