Report of the Department of Lands and Forests for fiscal year ending March 31, 1951 Page 116 



Forest Entomology 



Dr. C. E. Atwood continued to act in a consultancy capacity. During the past 

 year he made surveys of the following insect outbreaks in various parts of the 

 province: 



1. Spruce budworm, in Pembroke and Kenora areas. 



2. Larch sawfly, in the Kenora area. 



3. Pine-feeding sawflies, in many parts of the province, particularly the Sault 

 Ste. Marie and Quetico areas. The European spruce sawfly was discovered 

 in the latter area, a great extension of its previously known range. 



4. Yellow-headed spruce sawfly, general. 



5. Miscellaneous insects on spruce and maple. 



Dr. Atwood's connection with the Department helped him to maintain contact with 

 graduate students working on a number of projects in forest entomology, to mutual 

 advantage. 



The Division continued its co-operative arrangement with the Division of 

 Forest Biology. Department of Agriculture, Canada, with particular reference to the 

 Forest Insect Laboratory, Sault Ste. Marie. Dr. ]\L L. Prebble, Officer-in-Charge, 

 issues a separate report. 



Fisheries 



By co-operative arrangement. Dr. F. E. J. Fry of the University of Toronto 

 continues to direct fisheries research for the Division, with the assistance of N. S. 

 Baldwin, a member of the staff of the Division. During the past year the research 

 program was carried out at three main centres — the Department's Fisheries Research 

 Station at South Baymouth, IManitoulin Island; the Ontario Fisheries Research 

 Laboratory, Algonquin Park, and the Department's Southern Research Station, near 

 Maple. 



The South Bay Experiment: The damaging effects of large populations of undesirable 

 or coarse fish on the abundance of more desirable species have become a major concern 

 of both commercial and sport fishing interests. The purpose of the South Bay Experi- 

 ment is to determine whether a regulated net fishery which removes considerable 

 quantities of coarse fish would increase the production of commercial and game fish. 

 A committee representing all major interests is responsible for the conduct of the 

 experiment. The composition of this committee was outlined in last year's report. 



Since the initiation of the experiment in 1947 net catches of the more 

 important coarse fish reached a total number of 554,517, while the catch of valuable 

 species, largely whitefish, totalled 140,797 lbs. The average annual removal of 8 lbs. 

 of coarse fish per acre of water, while believed to be a comparatively high return for 

 these waters, has had no observable eft'ect as yet in reducing their abundance. The 

 net fishery has had neither a favourable or adverse effect on sport fishing. 



Age determination of fish by study of their scales has allowed certain predic- 

 tions in the case of the sports fishery. Lake trout fishing will decline in the next two 

 or three years as there is no evidence of young fish to replace the abundant age group 



