8 i» 



DONALDSON STRAIN RAINBOW TROUT 



n = 3 



10 30 60 



TIME (MINUTES) 



FIG. 1 Effect of stress and repeated sampling on blood clotting 

 times in a hatchery trout (top) and a wild trout (bottom); 



— — stressed group; control group. Each point represents 



the mean + s.e. Asterisk (*) indicates significant difference from 

 initial levels (P = 0.05). 



hatchery trout maintain a hypercoagulable condi- 

 tion for at least 5 hr. The corresponding increase 

 in numbers of thrombocytes is shown in Fig. 2 and 

 3. While the hematocrits increased (Fig. 4 and 5), 

 neither the counts of red cells nor white cells 

 increased, suggesting that the increased hemato- 

 crits resulted from increased cell volume. This 

 phenomenon has been observed before (Sovio and 

 Nyholm, 1973) when red cells were exposed to low 

 2 levels. 



Increases in plasma glucose have been identi- 

 fied as an indicator of the degree of stress in humans 

 and also in rainbow trout (Wedemeyer, 1972). The 



STRESS 



DONALDSON STRAIN RAINBOW TROUT 



10 30 



"h 



10 30 



TIME (MINUTESI 



FIG. 3 Effect of stress and repeated sampling on the number 



of circulating thrombocytes in the wild trout; stressed 



group; control group. Each point represents the mean ±s.e. 



10 30 



TIME IMINUTESI 



FIG. 4 Percent change of hematocrits from initial levels in 



response to stress for a hatchery trout; stressed group; 



control group. Each point represents the mean ±s.e. 



> +20 



Yi 



STRESS 



I 



LAKE CHESTER MORSE RAINBOW TROUT 



10 30 



TIME IMINUTESI 



TIME (MINUTESI 



FIG. 2 Effect of stress and repeated sampling on the number 



of circulating thrombocytes in a hatchery trout; stressed 



group; control group. Each point represents the mean ±s.e. 



Asterisk (*) indicates significant difference from initial levels 

 (P = 0.05). 



FIG. 5 Percent change of hematocrits from initial levels in 



response to stress for a wild trout; stressed group; 



control group. Each point represents the mean ±s.e. 



Asterisk (*) indicates significant difference from control level 



(P = 0.05). 



94 Casillas, Smith, D'Aoust 



