DURBIN ET AL.: STOMACH CONTENTS OF HAKE AND COD 



APPENDIX 1 



Estimation of the Instantaneous Gastric Evacuation Rate, R 



A number of factors may affect the instantaneous 

 rate of gastric evacuation, R. These include tempera- 

 ture, food type, food particle size, meal size, fish size, 

 autolysis of food in the stomach, swimming activity, 

 prestarvation, experimental stress, experimental 



error, and time lags between ingestion and the begin- 

 ning of gastric evacuation. 



R values from the more complete studies of marine 

 and freshwater fishes are presented as a function of 

 temperature in Appendix Figures 1 and 2. 



0.5 



a: «> 



i- a 1 



to 



< * 



o <* 05 



O t- 



o < 



uj cr 



z 



2 z 



z 9. 



*- < 



001 

 005 



001 



10 15 



TEMPERATURE , 



20 



25 



30 



'Author's calculation of R 



2 Our calculation of R, from dato presented in the study 

 and assuming evocuation is an exponential process 



APPENDIX FIGURE 1. — The relationship between the instantaneous gastric evacuation rate IR, 

 per hour) and temperature in several marine fishes. Note that the body temperature of Kat- 

 suwonus was probably greater than that of the water temperature shown here. Dashed line and 

 equation based on data from Tyler (1970, 2 -15 C). Ki«Jrboe (1978), Durbin and Durbin (1981), 

 and Huebner and Langton (1982). Source of data, where T = Table, F = Figure, and A = Appen- 

 dix is shown. 



0.5 r 



o 



LO o. 



< 



o - 

 cr 

 to 



=> UJ 



O i- 



UJ < 

 Z <E 



< 



Si 

 II 



< 

 > 

 UJ 



0.1 

 0.05 



0.01 

 0005 - 



^ v 



— R 

 Gadus 



0.001 



Platichthys 



pseudqpleurohectes 



Brevoqrtia 



Katsuhohus 



Hyoxqcephalus 



Helanqgrahhus 



__l L 



0.0106 e°- lllT 

 Tyler (1970) 1 Tl 

 Bagge (1977)2 F1 

 Daan (1973) 2 Fll 



KiiIrboe (1978) 1 Fl,2 

 Huebner 8 langton (1982) 2 T2 



. Durbin g Durbin (1981) 1 T3 



A Magnuson (1969) 2 F2 



 Bagge (1977) 2 F3,5 



□ Jones (197M) 2 AMI 



_1_ 



5 10 15 20 



TEMPERATURE. °C 



' Author's calculation of R. 



2 0ur calculation of ft, from data presented in the study 

 and assuming eve evacuation is on exponential process. 



25 



30 



APPENDIX FIGURE 2. — The relationship between the instantaneous gastric evacuation rate 

 (R, per hour) and temperature in several freshwater fishes. Sources of data as in Appendix 

 Figure 1. 



451 



