Frances district. Eight new trap nets were built for district 

 use; two nets were remodelled; nine were overhauled and 

 repaired; and seven were loaned out to districts. 



The staff at Maple participated in the collection of lake 

 trout and yellow pickerel eggs for hatchery purposes. They 

 provided numerous species of live fish for display at the 

 Toronto Sportsmen's Show and the Canadian National 

 Exhibition. In addition, they harvested smallmouth bass at 

 two locations to assist the Ontario Water Resources Com- 

 mission in their mercury studies; they transferred live 

 pickerel from Tunnel Lake to Aubrey Falls Impoundment in 

 northern Ontario; they harvested maskinonge in Lake 

 Scugog to assist researchers in the study of sarcomas 

 (lesions) on fish; and they gave instruction in the use and 

 care of impoundmg gear to department staff at the Forest 

 Technical School 



To augment or replace stock on hand, ten new trap nets 

 and three retainers were built, four gangs of gill nets were 

 hung, three small mesh trap nets were constructed for 

 Research Branch, and some 97 nets were overhauled and 

 repaired. 



Young anglers with rainbow trout. Mount Pleasant Provin- 

 cial Fistiing Area. Photo by C. Van Cemerden. 





FISHERIES MANAGEMENT UNITS 



Units are established on large and complex lake systems to 



inventory, plan and manage the fishery resource. 



New Units were established during the year on Lake 

 Huron at Owen Sound and on Lake Superior at Sault Ste. 

 Marie. The biologist in each will co-ordinate the activities 

 of several forest districts, assisting in the planning and im- 

 plementation of fishery projects designed to use fully the 

 commercial and recreational potentials of the two Great 

 Lakes. 



A biologist came on staff to co-ordinate the activities of 

 the ten Units and several, special fisheries investigations. 



Lake St. Clair. Unit quarters near the mouth of the Thames 

 River were partially renovated. Work priorities were 

 changed by the problems of mercury contamination in fish, 

 and personnel were involved in the provincial loans pro- 

 gram to commercial fishermen, and in studying the effects 

 of mercury pollution on the sport fishery . 



Lake Nipigon. With the sounding of Ombabika and Pijita- 

 wabik Bays, all the major bays in Lake Nipigon have been 

 surveyed. Investigations indicated that the large silt load 

 carried by the Little Jackfish River into Ombabika Bay has 

 affected bottom fauna within one-half mile of the river 

 mouth. Yellow pickerel were examined and tagged in the 

 V\'abinosh River to determine the dispersal rate of this 

 spawning population. In the same tributary, test-netting in- 

 dicated that a substantial number of whitefish use the river 

 for spawning. Northern pike were sampled and tagged in 

 Mclntyre and Bonner Bays to assess the harvest by com- 

 mercial and sport fishermen. Brook trout investigations con- 

 tinued on several tributaries of the lake. 



Bay of Quinle. Investigations to assess the commercial and 

 sport fisheries continued during 1970. The reduction in the 

 harvest of whitefish and yellow pickerel appears related to 

 environmental changes resulting from eutrophication. The 

 sport fishery for yellow pickerel in Hay Bay is presently sup- 

 ported by only the older year classes of fish. Approximately 

 850 yellow pickerel were tagged from the spawning runs on 

 four tributaries of the Bay of Quinte, to measure the ex- 

 ploitation by anglers and determine migration patterns. Unit 

 personnel surveyed 23 tributaries of Lake Ontario to define 

 the extent of sea lamprey populations. 



Kawartha Lakes. Came fish in Chemung and Buckhorn Lakes 

 were netted and tagged to determine migration patterns. 

 Scheduled creel surveys were used to determine angler suc- 

 cess, total harvest and rate of recapture of tagged fish. In 

 co-operation with Ontario Water Resources Commission, 

 Unit personnel began planning a special study of the effects 



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