THE BEHAVIOR OF BROOK TROUT EMBRYOS FROM 

 THE TIME OF HATCHING TO THE ABSORPTION 



OF THE YOLK SAC 



GERTRUDE M. WHITE 

 Zoological Laboratories, University of Wisconsin 



WITH FOUR FIGURES 



CONTENTS 



PAGE 



a. INTRODUCTION 44 



b. EXPERIMENTS AND OBSERVATIONS 46 



1. Hatching 46 



2. Swimming movements 48 



3. Reactions to mechanical jars 49 



4. Reactions to touch 49 



5. Reactions to current 49 



6. Reactions to light 52 



7. Reactions to current and light 53 



8. Carbon dioxide and light 54 



9. Reactions to shadows ' 55 



10. Feeding reactions 55 



c. GENERAL DESCRIPTION OF THE EARLY LIFE OF THE 



BROOK TROUT 56 



d. SUMMARY 59 



e. BIBLIOGRAPHY 60 



A. INTRODUCTION 



Although certain senses of mature fishes have been carefully 

 studied, little work has been done upon the reactions of embryos. 

 The investigations of the adult fish have been made chiefly with 

 reference to the senses of smell, taste, sight, and hearing. Her- 

 rick ('03) found that some fishes possess taste buds located in 

 the skin, by which they habitually discover their food, while 

 other fishes have the sense of taste confined to the mouth. That 

 the catfish has a true olfactory sense, which is distinct from 

 gustatory, was shown by Parker ('10). The sense of hearing 

 has also been studied by Parker ('05, '08, '11), who believes 

 that some fishes are stimulated by sounds of slow vibration. 

 Bernoulli ('10), on the other hand, maintains that the fishes 

 with which he worked do not hear, but respond through tactual 



44 



