compensated. At those temperatures, samples were analyzed by the 

 Winkler method. 



The diurnal rhythm of brown shrimp was taken into consideration 

 while determining the respiratory rates. Being nocturnal, the ani- 

 mals exhibit higher respiratory rates at night than in daytime. As 

 such, the nocturnal rates do not meet the criteria set forth for 

 standard metabolic rates by Gordon (1972). He stated that the ideal 

 standard metabolic rate should be an animal's metabolism under the 

 simplest and least physiologically demanding conditions. Therefore, 

 the oxygen consumption rates were measured between 1000 and 1200 

 hours when the animals were least active. 



Oxygen consumption in media with deviated ions 



Procedures for oxygen sampling in the deviated ion media were 

 essentially the same as in the previous oxygen study with some 

 changes. Shrimp were acclimated for one week at 25°C and 15°/ooS 

 as before. They were then separately tested in 15°/ooS at 18°, 25°, 

 and 32°C, with the following ion concentrations: 25-6 Ca, 0% Mg, and 

 30% K. The total test time was reduced to 24 hours and samples were 

 taken at 1, 2, 3, 4, 6, 10, and 24 hours. Shrimp were transferred 

 directly from acclimation tanks to the test chambers at hour. 

 Additional chambers were added in the system and supplied with 

 normal seawater to act as controls. 



Statistics 



Data from male and female shrimp were analyzed separately but 

 were combined for the general results: mean, standard deviation, 

 standard error. The t tests were done to determine the effect of sex 

 on mean blood ionic levels and osmoconcentration and on oxygen 

 consumption using the IBM 1130 Scientific Subroutine Package. The 

 t statistics for hourly oxygen consumption comparisons were computed 

 following the formula given by Sokal and Rohlf (1969). 



46 



