8 MARINE AND FISHERIES 



5 GEORGE v., A. 1915 



running water, there are in this region no species of which this type of surrounding 

 is characteristic. Some species, such as small-mouthed bass, pike, and pickerel, 

 prefer running water, but all are distributed without reference to this factor. 

 Such species as commonly inhabit running water elsewhere and are also present 

 in this region appear to select other situations of an open character. There are 

 in fact no permanent small streams, and no naturally flowing rivers in the entire 

 region. It is possible also that the lack of similar advantages, such as either 

 turbidity or exception purity, or minor conditions of food and shelter peculiar 

 to sedimentary bottoms, may tend to restrict the development of a great variety 

 of species in Archean waters. 



Finally, we may refer to certain differences in distribution which distinguish 

 parts of the Archean drainage area from one another or from Georgian Bay. On 

 this question, unfortunately, detailed information is lacking, so that only frag- 

 ments of evidence can be presented. Georgian Bay, for example, contains four 

 species of fishes which are definitely known not to occui in the Muskoka Lakes, 

 namely, the common pike, maskinonge, rock-bass, and green bass. Possibly 

 a detailed study of these lakes would reveal the absence of other smaller species 

 present in Georgian Bay, those named being the more conspicuous types. An 

 important fact concerning these species is that they occur in various situations 

 between the Muskoka Lakes and the Georgian Bay shore, and, moreover, that 

 the first three of them occur in the Musquash River within a short distance of Bala 

 Falls on Lake Muskoka. The absence of these species at the higher level has been 

 attributed to the presence of waterfalls, a point which has been commented on by 

 Meek and Clark ('02) ; but this factor would also affect the situation as regards 

 many other lakes. Moreover, it is a well-known fact that certain of the inland 

 lakes of the Muskoka and adjacent regions contain individually predominant 

 types of game fishes, so that they are sometimes characterized as bass lakes, 

 trout lakes or maskinonge lakes. This condition has led to the suggestion that 

 the bass lakes have become so through the introduction of the small-mouthed 

 bass in former times by Indians and through the tendency of this species to supplant 

 the trout where the two species come into contact. 



Whatever explanations may be brought forward either of natural barriers 

 or of intioduction by human agency, it can be shown that there are certain differ- 

 ences of distribution to which such causes cannot be assigned. These refer to the 

 presence at higher levels of species not found at the lower levels. Several cases 

 of the kind have come to light, the best example being certain species present 

 in Muskoka Lake and absent in Go Home Bay. Muskoka Lake contains five 

 species, namely, the speckled trout {Salveliiius fontinalis) , found in some of the 

 streams, the black catfish (ATneiurus melas), and three species of minnows 

 (Semotilus atromaculatus, Hyhognathus nuchale, and Chrosomus erythrogaster) , all 

 of which are reported by Meek and Clark ('02). These species either do not 

 occur at all or if present do not occur naturally at the lower level of Go Home 

 Bay. It thus appears that there are certain differentiating factors, which may 

 be based on observed differences, such as soil content, food supply or water com- 

 position upon which the presence of certain species will be found to depend. 



