FISHERIES SECTION 



GREAT LAKES UNITS 



LAKE ONTARIO UNIT 



The whitefish fishery continued to show improvement 

 following experimental closure for spawning fish on lake- 

 shore grounds. There are no indications of a return of the 

 Bay of Quinte whitefish spawning runs. 



The first of three scheduled plantings of yearling splake 

 amounting to 24,000 was completed. Commercial fisher- 

 men will be paid for the return of any of these taken in 

 their nets. Spawning is not anticipated before 1970. 



A survey by the vessel Namaycush included investiga- 

 tions of near-bottom dissolved oxygen conditions in mid- 

 July and mid-August. No areas of oxygen depletion were 

 noted. 



An important analysis was made on the relationship be- 

 tween numbers of smelt netted and size of net mesh. 



Environmental monitoring at several locations indicate 

 significant increases in phosphates and nitrates in the past 

 four years. 



A program of tagging and releasing American eels has 

 been in progress since 1958. Physical characteristics have 

 been placed on computer cards to produce a morphological 

 index of maturity. The commercial catch continues to 

 decline. 



Results in attempts to introduce the kokanee, a pelagic, 

 plankton feeder in its native waters, into Lake Ontario have 

 so far been negative. Studies of the downstream behavior 

 were made in the laboratory and in Shelter Valley Creek. An 

 additional 228,000 fry were planted in Shelter Valley Creek, 



LAKE ERIE UNIT 



Fish stock were monitored by sampling commercial catches. 

 This provides a substantial body of data at minimum 

 expense. 



A year-to-year Index for relative abundance of all fish 

 species was established by experimental fishing. This is 

 useful in predicting, at least qualitatively, the success of 

 commercial fishing for these species one or two years 

 hence. 



Studies continue on the timing of smelt runs in relation 

 to weather, and vital statistics of the spawning fish have 

 been thoroughly documented. Incidence of the parasite 

 Glugea remains high, but there is no evidence yet of 

 mortality. 



Walleye spawning areas were surveyed and described. A 

 study of the productive potential ot Thames River Walleye 

 was initiated and will continue. A study on movements of 

 this species was completed and reported. 



LAKE HURON UNIT 



Experimental pound-net samplings show a continued de- 

 cline in abundance of alewives, an increase in ciscoes, a 

 stable pattern in whitefish and a decline in both yellow 

 perch and suckers. 



Gill net surveys in southern Lake Huron indicate a situa- 

 tion common to the whole lake, that undesirable species 

 dominate the catch. 



Smelt index stations indicate a decline in this species. 



Studies of young whitefish would seem to indicate that 

 year-class strength is determined by survival at the egg 

 stage rather than elsewhere in its life history. 



Commercial catches of whitefish are sampled to describe 

 the dynamics of growth, mortality and exploitation of the 

 population and to segregate total mortality into components 

 attributable to fishing and non-fishing causes. 



Branding splake. 



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