24 DEPARTMENT OF GAME AND FISHERIES No. 9 (1943) 



members of the Laboratory. The lakes which were stocked are included in the list in 

 Appendix No. 1 under the District of Nipissing. 



The experiment on the alternate annual closure of lakes was continued. The 

 purpose of the experiment was to determine the value of the alternate annual closure 

 of lakes as a means of increasing and maintaining the stock of game fish in those 

 waters. As a part of this plan, lakes adjacent to one another are closed in altern- 

 ate years so that any area will have lakes open to fishing each year, and lakes which 

 are closed and in which the stock is given every opportunity to increase. In this way 

 anglers taking a trip through the Park will find waters open to angling along any 

 canoe route which they wish to travel. 



The 21 lakes which were closed in 1940 were open in 1941, and in 1941 there 

 were 17 other lakes closed which will in turn be open to fishing in 1942. 



The results of the closures are now becoming evident. The speckled trout are 

 showing an immediate favorable response, and the lake trout are responding favorably, 

 but more slowly because of their slower rate of growth. The total result is that there 

 is an increase in the number of fish available to the angler and the fish are showing 

 an increase in size as a result of the closure. These favorable results are much more 

 marked in some lakes than in others. 



It is most desirable to carry on this procedure for some time yet on the experi- 

 mental basis to properly evaluate its influence upon both the speckled trout and the 

 lake trout in the different lakes. 



The rate at which speckled trout grow is quite well known as they have been 

 raised in hatcheries where they are often kept for years and the growth of wild trout 

 has been determined by studies of the rings formed on the scales. Little is known 

 about the rate of growth of lake trout and yet this information is necessary if we are 

 to understand the results of the closure of lakes on the lake trout fishery. To this 

 end a study of the rate of growth of lake trout in two Algonquin Park lakes has been 

 started by Dr. Fry who has found in general that lake trout show approximately the 

 following age-length relations: 



Age in years Length in inches 



3 8 



4 10.5 



5 11.5 



6 12.5 



7 13.5 



In order to evaluate more completely the stocking of the lakes and the alternate 

 annual closure it is most important that the anglers continue their co-operation as 

 they have in the past with the collection of complete creel census of all species of fish 

 taken in all the waters of Algonquin Park. 



With the demands of war taking its toll upon the staff of the Fisheries Laboratory 

 this co-operation of the anglers is increasingly important and valuable as the reduced 

 staff of the Laboratory is finding it increasingly difficult to carry out all the work 

 necessary to measure these fish cultural activities, so that we look to the anglers for 

 increased assistance in this field. 



The stocking of the lakes, the alternate annual closure, and the measurement 

 of the results of these methods are the most important fish cultural activities of the 

 Laboratory as a war measure. Most of the other activities have been reduced to a 

 minimum for the duration. 



