population in recent years suggests that this may be the next traditionally important 

 species to follow the ciscoes, whitefish and blue pike to virtual elimination in the 

 rapidly changing environment of Lake Erie. Periodic successful reproduction and 

 a high level of abundance of walleyes in neighboring Lake St. Clair leave some 

 hope if successful management of a major research programme could be quickly 

 launched. The present lack of information on walleyes has contributed to con- 

 troversy, not only between fishermen and the Department, but also between con- 

 servation agencies. 



Our present small research program is concentrated on one of the presently 

 important species, smelt. 



Studies of the many smelt spawning populations over the past several years 

 have shown that they are all essentially the same. Size, age, sex ratio and electro- 

 phoretic (blood chemistry) analyses have shown no important differences. This 

 sameness means that smelt can be managed as a single population in Lake Erie. 

 This is in contrast with, for example, lake trout in Lake Superior and whitefish 

 in Lake Huron where a number of discrete populations, requiring different man- 

 agement techniques, have been demonstrated. 



Studies of the food of smelt have not confirmed our suspicion that cannibal- 

 ism might be the explanation for the alternate strong and weak year classes of 

 smelt which cause fluctuations in the numbers available to fishermen. The diet of 

 yellow perch is being closely examined now. 



A study of the distribution of smelt in Lake Erie was completed during 1965 

 and the published report has proven to be of value to both management and 

 industry. 



As time permits, the yellow perch data which has been accumulated during 

 net-run sampling is being analyzed with respect to year class dominance. The de- 

 velopment of index stations which will, we hope, provide data basic to predictions 

 of fishing conditions for important species two or three years hence is proceeding. 

 This project seems of particular importance in the rapidly changing Lake Erie 

 situation. 



LAKE HURON 



The research programme on Lake Huron was established in the late 1940s 

 when the native lake trout population was disappearing. Study by our research 

 staff of that disappearance, and of the subsequent disappearance of artificial 

 (planted) lake trout populations, clearly demonstrated that the sea lamprey was 

 the principal cause of the decline. This research provided the basis on which the 

 international program of sea lamprey control has been erected. Since that time, 

 the mid-1950s, the most important species in the lake has been whitefish and 

 our research has been concentrated on this species. Of principal concern is the 

 wide variation in year class success which causes fluctuations of abundance from 

 year to year. The several discrete whitefish populations which have been discov- 

 ered in Lake Huron have been followed closely in hopes of discovering the causes 

 of these fluctuations. Southern Georgian Bay provides a home for one of these 

 separate populations and a study of this population was completed in 1965 and 

 published in the Journal of Fisheries Research Board of Canada. This study 

 showed that exploitation has been relatively high over the past decade and sug- 

 gested that management should not increase the present level of harvest. In South 

 Bay favourable progress is being made in studies of very young whitefish about 

 which little is known at present. It is thought that year class strength may become 

 established during the spawning or hatching period, or during the first season after 



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