Report of the Department of Lands and Forests for fiscal year ending March 31, 1950 Page 126 



Tagging studies of fish caught which were previously captured, tagged and 

 released reveal important information as to migrations in and out of South Bay which 

 opens into Lake Huron through a narrow channel, and as to movements of fish within 

 the bay. For example, intensive studies in 1949 show that only a few lake trout 

 leave the bay, and these during the winter. Whitefish. on the other hand, move out of 

 the bay in considerable numbers during early summer. Bass show no tendency to leave 

 the bay, but move freely from place to place in it. 



Further investigation was made in 1949 as to methods of preparing and dis- 

 posing of coarse fish products. Sucker fillets frozen while fresh have proved deliciously 

 palatable, and there is promise of a small but flourishing market outlet for this product. 

 Fish meal and oil extracts have been prepared experimentally in small quantities. 



During 1949 a start was made in a study of the effects of lamprey preying on 

 whitefish and lake trout. 



Routine study continued on food habits and growth of a wide variety of fish 

 species. 



Ontario Fisheries Research Laboratory, Algonquin Park. A variety of 

 projects are being undertaken co-operatively between the L^niversity of Toronto and 

 the Department, centering at the laboratory at Opeongo Lake. Brief accounts of 

 the main projects follow: 



Ckeel Census. This recording of fishing success, initiated in 1936, has two 

 main purposes. First to follow trends in fishing success in Algonquin Park and thus 

 allow the Department to decide which lakes require attention, and secondly to find out 

 whether management techniques such as plantings, lake closures, and chemical 

 fertilization have any effect in improving fishing. 



The census has disclosed a downward trend in lake trout fishing success in the 

 more accessible southern part of the Park. Plantings have been undertaken to improve 

 this situation. Speckled trout fishing, although fluctuating, has shown no trend in 

 recent years. Plantings of speckled trout have had little effect in improving fishing 

 in recent years. Closure of lakes in alternate years has been adopted to build up wild 

 stocks of trout in many of the lakes. 



The effect of transferring small mouth bass from lakes in which they are 

 crowded and grow slowly to lakes where food is more abundant is also being studied. 



Fertilization of Lakes. In the period 1946 to 1949 fertilizer was applied in 

 Cache, Brewer, Kearney and McCauley lakes to determine whether this would increase 

 the production of game fish. Costello, Clarke and Found lakes were left untreated 

 for check purposes. 



A marked increase was noted in phytoplankton and zooplankton populations 

 and bottom fauna in the fertilized lakes, and produced a distinct bloom on the algae. 

 A corollary and undesirable effect noted was depletion of oxygen at lower levels, due 

 to decay of the increased quantity of plant and animal debris. However, several 

 species of smaller fish showed an increase in numbers. It appears that under nine 

 pounds of fertilizer to the acre-foot are desirable for continued applications to trout 

 waters. 



Spawning Habits of Speckled and Lake Trout. The study in 1949 of 

 speckled trout spawning in Algonquin Park lakes indicates that they prefer gravel and 



