determine the effect of combined angler and commercial 

 fishing pressure on yellow pickerel and lake trout, the most 

 Important species. Creel census work in 1968 was intensified 

 to provide better estimates of total harvest, and trap nets 

 were operated to determine if significant changes had 

 occurred in the yellow pickerel population since the 1965-6 

 survey. On a lake-wide basis, the abundance of yellow pick- 

 erel had not declined but more younger, smaller, faster- 

 growing fish with decreasing natural mortalities were noted. 

 A summary of the work on Sturgeon Lake indicated that 

 yellow pickerel and lake trout were under considerable 

 fishing pressure. On this basis, some adjustment of com- 

 mercial quotas was made. 



Lac Seul. This large lake in Sioux Lookout Forest District has 

 been a hydro reservoir of some 500 square miles since 1929 

 when the dam was built. The amount of water storage and 

 subsequent draw-down approximates 14-16 feet annually. 

 Ten tourist camps and thirteen commercial fishing opera- 

 tions are located on the lake, and it has been hypothesized 

 that fluctuating water levels are limiting fish production. To 

 investigate this possibility, a biologist and two students were 

 assigned to work on Lac Seul during the summer of 1968. 

 Past records of commercial fishing activity were examined, 

 and comparisons made with more recent harvest statistics. 

 The trend appears to be downward, but the cause is not as 

 yet clear. In the summer of 1968, sounding and water sam- 

 pling of the basin were initiated to provide data on the po- 

 tential productivity of the lake. Approximately 50 per cent of 

 the required work was completed in 1968 and the program 

 will continue. 



Bark Lake. This long-term project was initiated in 1965 in 

 Pembroke Forest District to determine the effect of the 

 extensive winter drawdown on the natural reproduction of 

 lake trout. To date, approximately 500 adult lake trout have 

 been tagged, and some interesting recaptures recorded. 

 Also, 60,000 marked lake trout yearlings have been stocked 

 to determine the contribution made to the fishery as com- 

 pared to that of natural reproduction in years of severe water 

 fluctuation. In 1968, an effort was made to determine the 

 incubation period of lake trout eggs under natural condi- 

 tions In Bark Lake. Fertilized eggs were placed in screened 

 boxes in the lake on October 12th, and it was discovered 

 that 30 per cent of the eggs had hatched by December 5th. 

 This indicated that the minimum incubation period approxi- 

 mated 55 davs. The work will be continued to establish an 

 average incubation period for lake trout in Bark Lake. The 

 project Is expected to continue until 1975. 



Georgian Bay. The site of the Georgian Bay yellow pickerel 

 study was moved from the Shawanaga basin to the Moon 

 River area in the spring of 1968. Trap-netting operations 



22 



were carried on from April 23 to May 21 and again in the 

 summer from August 1 to August 30. A total of 4,440 yellow 

 pickerel was captured. Preliminary estimates indicate a 

 spawning population of approximatelv 21.000 fish. It is ap- 

 parent from tag returns that a relatively widespread popu- 

 lation of yellow pickerel utilize the Moon River spawning 

 site, and there is the possibility that two discrete populations 

 are present. Creel census studies continued at the Moon 

 River and Shawanaga sites. Movements of yellow pickerel 

 from the latter, as evidenced by tag returns, showed that they 

 concur with those of previous years. 



Ouananiche (Atlantic Salmon) Fishery, Trout Lake. During 

 1968, a decision was made to take action to preserve and 

 support this attractive fishery in North Bay Forest District. 

 Preliminary steps were taken to acquire the land along the 

 lower reaches of Four Mile Creek to prevent a proposed 

 development which would destroy spawning areas. Thirty- 

 six acres were purchased in the spring of 1969. 



36-inch maskinonge taken at Balsam Lake, Lindsay Forest 

 District. 



