100 



a 



z 



z 

 < 



cc 



Q 



o 

 o 



u. 



z 



LU 



o 



oc 



UJ 



a. 



lOOi 



10C 



r=-.869 



N:39 



Y = 98.9-2.60X 



20C 

 r=-.971 



Y:118.2-8.21X 



TIME(HOUR) 



Figure 1.— The percent dry weight of juvenile chinook salmon remaining in the digestive tract of force- fed Sacramento squawfish after 

 specified digestion periods at 5°, 10°, 15°, and 20°C. Each squawfish was fed four salmon. 



The mean time for complete gastric evacuation 

 over tlie temperature range examined can be cal- 

 culated using a curvilinear equation in the form: 



logGE = 1.996 - 0.045T (1) 



where GE = gastric evacuation (h) 

 T = temperature (°C) 



Although other equations may be equally applicable, 

 Equation (1) fits the data well {r- = 0.978, Fig. 2). 



Discussion 



The digestion and gastric evacuation rates of 

 Sacramento squawfish in relation to temperature 

 differ in some respects than for the northern squaw- 

 fish. The gastric evacuation times of the Sacramento 

 squawfish in this study are different from the times 

 calculated from equations presented in Falter (1969) 



5.0 



4.0 



(V 



o 3.0 



cc 



O 



X 



LLl 



I- 



2.0 



1.0 



5 10 15 20 



TEMPERATURE (ISX) 



Figure 2.— Estimated time for complete gastric 

 evacuation of Sacramento squawfish force-fed 

 four juvenile chinook salmon at 5°, 10°, 15°, and 

 20°C. 



161 



