28 DEPARTMENT OF GAME AND FISHERIES . No. 9 



to a maximum of thirty-six inches. In some lakes the lake trout are mostly small 

 and in other lakes there is a preponderance of large trout, while still other lakes 

 contain trout varying in size from small to large. The size and number of trout 

 in a lake is related to the available food and the amount of fishing. This infor- 

 mation which has been made available as a result of the cooperation of the anglers 

 and the biological investigations of these lakes has made possible the carrying out 

 of experiments of value in fish culture. 



In these lakes where the food scarcity is the controlling factor arrangements 

 are being carried out to improve the food condition by introducing small food fish. 

 In those lakes where excessive fishing is depleting the stock of lake trout, two kinds 

 of experiments are being undertaken. In lakes adjacent to the highway or in the 

 vicinity of cottages trout of different sizes are being planted and the result of 

 this stocking will be determined. Some lakes which are remote from the highway 

 are being closed to fishing in alternate years and the improvement in fishing resulting 

 from this closure is being measured during the years in which those lakes are open 

 to angling. 



It is most desirable to have definite information on the trout population in 

 lakes. The particular relationship of White lake to Big Trout lake in Algonquin 

 Park makes it possible to ascertain the trout population of White lake for at least 

 part of the year. These two lakes are joined by a narrow channel 100 feet wide 

 and about 12 feet deep. White lake with an area of 1040 acres and a maximum depth 

 of 40 feet has lake trout in it during the fall, winter and spring. As it warms up 

 during the summer, the lake trout all move out into Big Trout lake which is much 

 deeper. In the spring and early summer of 1939 all of the lake trout moving out of 

 White lake were captured in a fyke net, measured, and released into Big Trout lake. 

 By July 10 all of the lake trout had moved out. There were 813 between twelve 

 and twenty-eight inches in length, with a total weight of about 2177 pounds. Thus 

 White lake with an area of 1040 acres supports about one lake trout of fishable 

 size per acre or about two pounds of available lake trout per acre. 



The young speckled trout in Algonquin Park waters live in the stream during 

 the early part of their lives. Here they feed upon aquatic insects. Studies of these 

 insect populations have given astonishingly large numbers for the production of this 

 trout food. From May 17 to September 11, 1939, one square yard of water in a 

 typical trout stream inhabited by trout was found to produce during the summer 

 550 mayflies, 700 stoneflies, 466 caddis flies and 4,400 blackflies and midges, as well 

 as some other aquatic insects, all of which constitute excellent trout food. 



Bass from some lakes and rivers in the Park have fish parasites. None of 

 the fish parasites are injurious to man but they are unpleasant for the angler to 

 find while cleaning the fish. A study of the distribution of these parasites has been 

 carried out to find where they occur most abundantly. With this information at 

 hand the danger of transferring parasites from one body of water to another can 

 be reduced to a minimum. 



A small hatchery has been established near Algonquin Park headquarters, 

 where fish which have been raised in the rearing stations of the Ontario Department of 

 Game and Fisheries may be held for some time and from where they may be con- 

 viently distributed to any desired water in the Park." 



ACKNOWLEDGMENTS 



The assistance and co-operation rendered during the year, particularly by 

 Fish and Game Protective Associations and members thereof, have indeed been very 



