24 DEPARTMENT OF GAME AND FISHERIES No. 9 (1942) 



Toronto in September. At Tea lake dam an opportunity was afforded of investigating 

 the feeding of speckled trout. Quantitative collections of the insects emerging from 

 the water which form a large percentage of the trout food were made and trout were 

 taken and their stomach contents are being examined to find what elements of the 

 food available to the trout are eaten by them at different times of the day and year. 

 During this study it was noted that the trout were absent from the rapids^,below the 

 dam from approximately the 20th of July to September 1st. 



Work carried on in the experimental laboratory at Opeongo was concerned with 

 various ways in which environment may affect or limit the activitie^s of fish. An 

 investigation of immediate practical importance to our technique of restocking was 

 to ascertain what surface temperatures might be considered unfavourably high for 

 Hhe planting of speckled trout. It was found that speckled trout, straight from the 

 holding troughs, would die within twenty-four hours if placed in water at 73° F. 

 Further, the gradual equalizing of the temperature of the water in the fish can to 

 that of the bath over a period of fifteen minutes gave no appreciable benefits. How- 

 ever, by first exposing the fish to a moderately high temperature for twelve hours 

 (65° F.) it was possible to raise the lethal temperature from 73° F. to 79° F., even 

 although the fish had been returned to cooler water over night. A study of the lethal 

 temperatures of the various species of fish in the waters of the Park was begun. 



Studies on the respiratory tolerance of fish were continued, and experiments on 

 the circulatory capacity of fish were conducted by measuring the volume of blood 

 passed by the heart at each stroke. This apparently differs widely in different species 

 of fish and we believe it may be one of the differences between those fish which 

 can live in warm water and those which cannot. 



ACKNOWLEDGMENTS 



The Department is indebted to the Ontario Federation of Anglers and Hunters 

 and its many constituent Fish and Game Protective Associations throughout the 

 Province and to the Northern Ontario Tourist Trade Association, as well as to 

 interested sportsmen and conservationists for their active co-operation and splendid 

 assistance in the protection of the provincial fish and game resources. . The activ- 

 ities of these Associations and individuals have undoubtedly played a prominent part 

 in developing the spirit of conservation now prevalent in the Province, and have 

 materially helped to make our work in the Department more agreeable and pleasant. 



In closing this report I desire to make reference to the work of the staff. 

 Members of the service, both inside and outside, generally have been conscientious 

 in the performance of their work, and courteous in their contacts with the public, 

 in an endeavour to assure the best results. 



All of which is respectfully submitted. 



I am, Sir, 



Your obedient servant, 



D. J. TAYLOR, 



Deputy Minister of Game and Fisheries. 



