The brown shrimp acclimated to and tested at 18°C (Fig. 37) ex- 

 hibited the same initial response pattern as the shrimp acclimated to 

 25°C showed with respect to different salinities. This was also true 

 in animals tested at 25°C (Fig. 38) and 32°C (Fig. 39). Within two 

 to six hours after transfer, stabilization commenced in most of the 

 salinities. However, in 36°/ooS it was a very slow process, taking 

 place after the third day at 18°C and 32°C (Figs. 37 and 39, respec- 

 tively) and on the fourth day at 25°C (Fig. 38). In the course of 

 stabilization individual shrimp showed greater fluctuations in 25°C 

 than in 18° or 32°C. Also the fluctuations were higher in 25 and 

 36°/ooS than in lower concentrations. New steady-state levels ap- 

 peared in 2, 5, 10, and 15°/ooS at the three test temperatures but 

 not in 25 or 36°/ooS. 



Potassium ion regulation 



The brown shrimp acclimated to 25°C and tested in 25°C (Fig. 

 40), 32°C (Fig. 41), and 18°C (Fig. 42) experienced an initial drop 

 in the potassium ion concentration in 2, 5, 10°/ooS and sometimes in 

 15°/ooS. In 25 and 36°/ooS there was a simultaneous increase. The 

 duration of the initial drop varied from one to two hours in 5 , 10, 

 and 25°/ooS and from six to ten hours in 2 and 36°/ooS regardless of 

 water temperature. 



The stabilization process started within the first day in most 

 of the conditions. The process continued through the fourth day 

 until steady-state levels were established. During stabilization, 

 fluctuations in potassium regulation increased in test temperatures 

 25° and 32°C. New steady-state levels were observed in most of the 

 conditions between the fourth and seventh day. However, except on 

 the basis of moving averages, it was not possible to conclude from 

 actual values whether new steady states were obtained in 10 and 

 15°/ooS at 25°C (Fig. 40) and in 2 and 5°/ooS at 32°C (Fig. 41). 



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