replicate plantings have been made since. The survival of hatchery plantings 

 have been reported in Section Report (Fisheries) #51 and indicate a low, but the 

 best, survival in lakes where minnows are the only other species present. Poorest 

 survival is evident when suckers are also found in the lake. 



Studies of the relationship between white suckers and brook trout have been 

 started because of the relationship reported above. Other projects include an 

 attempt to develop a simple technique for providing artificial spawning beds to 

 allow natural reproduction where these are lacking, as is the case in a large 

 number of brook trout producing waters, and a study of the usefulness of fish 

 toxicants as a tool of brook trout management. 



SMALLMOUTH BASS 



A relationship has been discovered between average summer temperatures and 

 bass year class strength. On th basis of air temperatures at Lake Opeongo to be 

 measured in the summer of 1965, the quality of angling for bass in the years 1968 

 and 1969 can be predicted. Such predictions have been made successfully for 

 South Bay and Lake Opeongo. Further research is being undertaken to learn how 

 this relationship works, and why it applies only to the northern and not to the 

 southern waters of the province. 



Tests are also under way to assess the survival of planted, hatchery-reared 

 bass fingerlings. 



WALLEYE 



Most of the 1964 field season was spent in exploring a number of waters to 

 locate the best site for the long-range ecological study of walleyes, which is 

 considered the best approach to improved management of this species. Underwater 

 observations will form an integral part of this programme. The complex of lakes 

 (Baptiste, Elephant, Benoir) and the York River was chosen, and a headquarters 

 was established. 



The principal observation made in this initial year of field work was that 

 walleyes lie in contact with the substrate, are generally in less than 10 feet of 

 water, on muddy and weedy bottoms. No walleyes were seen in or below the 

 thermocline. 



Four years' data covering the period 1955-1958 inclusive, are now being 

 compiled. Walleyes spawning in the Nipigon River show an annual migration 

 pattern, the bulk of the population moving from Lake Superior again in the fall 

 months. On the basis of tagging studies, the walleyes in Nipigon Bay are quite 

 discrete from the Black Bay population. Static estimates of the adult walleye 

 population have been made, using a modification of the Peterson estimate. 



The data on the Nipigon Bay walleyes is especially valuable, as investigations 

 this spring indicate a serious decline in the abundance of this species and possibly 

 the complete eradication of a spawning stock. 



The bibliographic compilation started in 1963, is continuing, and about 400 

 separates have been reviewed and catalogued by author, species and subject 

 matter. 



LIMNOLOGY 



Staff of this research unit are engaged in three activities: (1) co-ordinating 

 the collection of physical, chemical and plankton data undertaken by several of 

 our units in connection with various fisheries research projects; (2) acting in a 



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