Biological Survey — Oswego Watershed 27 



Leger,* after studying the biogenic capacity of certain streams 

 in France, concluded that the nutritive richness is proportionately 

 much greater in narrow than in wider streams. In streams above 

 5 meters in width, the richness in food diminished one-half at a dis- 

 tance of 2 or 2V2 meters from the banks. Although this has not 

 yet been proved to hold for New York streams, we shall have to 

 assume that it is true pending future quantitative determinations. 

 With this qualification then, we may calculate the number of fish 

 to be planted in streams more than 16 feet (roughly 5 meters) 

 wide using the following formula: 



1/2 m w + 8 m — X 



m = number of fish recorded in Table 8, for a stream one foot 



wide, 

 w = average width of stream to be stocked. 

 X=number of fish desired. 



It must be understood that the above values are merely rough 

 estimations subject to change as more information comes to light. 



Miscellaneous Considerations. — Brook Trout versus Brown 

 Trout: Which of the two species should receive priority in plant- 

 ing? In talking with various anglers with reference to this ques- 

 tion difference of opinion is evident. There is the feeling, prob- 

 ably of the majority, that native brook trout should be encouraged 

 in all fishing waters entirely suitable for them, because among 

 other reasons, their range is gradually becoming more restricted 

 by numerous adverse agencies. The desire to preserve this Amer- 

 ican species in as many localities as possible in order that its con- 

 tinued existence may be assured for coming generations, is entirely 

 logical and commendable. Yet there is a growing tendency, pos- 

 sibly among the minority, particularly in those regions where it is 

 the most abundant species, to become dissatisfied with the size to 

 which the brook trout attains and to wish to displace it with the 

 larger brown trout. 



It is the general belief among fish culturists that the two species 

 are incompatible and should not be placed in the same stream. 

 There is some evidence to bear this out. It is well to note, how- 

 ever, that the brook trout have not in all cases been crowded out 

 or exterminated by the browns, but have held their own in many 

 of the colder streams in which the most favorable conditions for 

 the brook trout are to be found. 



It may be pointed out that in the entire Oswego watershed the 

 total stream area for which brown trout have been recommended 

 is more than two-thirds greater than that for brook trout. It would 

 thus seem that there is a sufficient stream area to be found in the 

 warmer streams for brown trout enthusiasts without trying to ex- 

 tend the range of this species to the typical brook trout streams. 

 For this reason we have consistently advised the restriction of 



* Leger, L. 1910. Principes de la Methode Rationnelle du Peuplement des 

 Cours d'eau a Salmonides. Travaux du Laboratoire de Pisciculture de 

 L'Universite de Grenoble, fascicle 1, p. 531. 



