HIGHER ANIMALS IN ECONOMY OF LAKES 



137 



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Fig. 



Average Jencfth of F/sh landed mches 



I. Eelation between average length of lake trout captured in certain Algoncjuin Park, Ontario, 

 lakes and their availability as expressed by the number of fish captured per 100 boat-hours. 



are made up either of individuals capable 

 of abundant reproduction, or perhaps not 

 capable of any at all. Hence in the former 



case they may be maintained at a relatively 

 high density, or in the latter they will in 

 extreme cases practically disappear. Lake 



