134 U.S. BUREAU OF FISHERIES 



An examination of the stomach contents showed that in spite of 

 the fact that these trout had been reared solely on artificial food they 

 began to take natural food shortly after being liberated. The stom- 

 achs of fish caught the following day were filled with insects of vari- 

 ous kinds showing that they were on the alert for natural food from 

 the start. It was found that, in general, there was a slight increase 

 in the amount of food eaten during the first 3 days but that after 

 that there was little difference from day to day and that the amount 

 of food taken was approximately the same as by wild fish. It would 

 appear from this experiment that hatchery fish are fully able to forage 

 for themselves as soon as liberated. Owing to the great importance 

 of this problem further experiments along the same line will be 

 undertaken in the near future. 



Several experiments for the purpose of gaining information regard- 

 ing the behavior of fingerling trout when first hberated were carried 

 out at the Leetown station. Fingerling rainbow, brook, and brown 

 trout were liberated in a small spring-fed stream and their movements 

 carefully watched. The fish all showed a marked tendency to move 

 in schools for several days at least after being liberated. A general 

 tendency was noted for the fish to remain for some time in the pools 

 in which they had been planted although there was a gradual dispersal 

 along the stream. In this dispersal the rainbow trout moved more 

 quickly downstream than upstream while the opposite was true of 

 brook and brown trout. 



In all cases the fish began taking food almost immediately after 

 being liberated and examination of the stomach contents showed 

 they were feeding on aquatic insects and Crustacea. There was no 

 evidence that the hatchery-reared fish were not able to capture these 

 organisms as readily as wild trout. A marked increase in the bril- 

 liancy of the coloration was noticed within 2 weeks after the fish were 

 liberated. 



CALIFORNIA TROUT INVESTIGATIONS 



Work on problems relating to the trout of California has been vig- 

 orously pursued during the past year. Early in July Dr. H. S. Davis 

 and Dr. P. R. Needham were sent to California and in company with 

 A. C. Taft made an extensive survey of the better fishing areas of 

 the State with a view toward the development of a more intensive 

 program of field investigations. At a conference held in San Fran- 

 cisco with the officials of the California Division of Fish and Game a 

 new joint cooperative program was adopted which provides a com- 

 prehensive plan of study to be followed over a period of years. Dr. 

 Davis returned to Washington in late August and the field staff now 

 consists of Dr. Needham and Mr. Taft of this Bureau and two assist- 

 ants, Leo Shapovalov and Francis Sumner, who were appointed to 

 the work by the State. 



Briefly, the program as now set up consists in attacking the trout 

 problems of California from two angles; viz, a study of the trout and 

 a study of their natural environment. The data obtained in these 

 investigations will be utilized in the formulation of a scientific stock- 

 ing policy for the waters of the State. The major projects selected 

 for study are as follows : 



1. A study of the species and races of trout to obtain as complete 

 information as possible on the life history, habits, and ecological 

 requirements. 



