Biological Survey — Genesee River 7 



the problems of natural production and increase. In this initial 

 survey, therefore, it is not attempted to state a hard and fast rule 

 applicable to the different t.ypes of stream, a formula, that is, 

 which would have the advantage of an established standard upon 

 which to grade the numbers up or down though this should be 

 the goal for the future. For the present the mode of procedure 

 is by recommendation for each individual stream in the system. 

 .Map's of the U. S. Geological Survey (Maps l-o) have been 

 adai)ted to the pur])oses of record and all streams are shown 

 tliereon with suitable indications of dry and ])ermanent 

 streams, the presence of springs, pollution outfalls, and favorable 

 ])laces for fish ])lanting. Accom])anying the maps are lists 

 (App. IX-XITT) which set forth in tabular form the names of the 

 streams (if not named then numbered), the mileage available for 

 stocking and the stocking ])olicy per mile. By reference to these 

 tables and maps as guides the location of the best ])laces to plant 

 fish and the calculation of the number ])er mile may be 

 determined readily. 



Pollutional Conditions in the Genesee River System. — The 

 chief objective in directing studies ui)on this subject has been to 

 secure information which would picture fairly and adequately the 

 conditions of ])ollution existing throughout the watershed. For 

 this i)ur])ose data were obtained during tlie summer months when 

 pollutional conditions are generally at their worst and the effects 

 upon the stream life are most sharply marked. Both biological 

 and chemical studies were made and the results obtained give a 

 helpful interpretation of the situation. 



The dissolved oxygen ])rofile of the river system (Fig. 5) pre- 

 seuts an imi)ressive ])icture of the effect u])on the oxygen supply of 

 a succession of pollution outfalls, and re})resents most graj^hically 

 the cumulative effect of excessive and continuous overloads upon 

 the stream despite the increased volume of water in the lower 

 stretches of the river. The detailed data show in an interesting 

 manner as regards oxygen depletion and recovery the contrast 

 between the portions of the stream which are rapid and riffly and 

 those which are sluggish and unruffled where except for the bene- 

 ficial effects of plants and other sources the stream reoxygenates 

 only by slow absorj^tion from the surrounding atmos]ihere. Hence, 

 one is impressed with the need of taking into consideration at all 

 times the character of the stream. 



The evidence from the biological investigations is equally in- 

 structive and interesting. The types of i^olluting substances which 

 enter the river system are discussed in their relation to fish life 

 and to the organisms associated with them in the capacity of food 

 of fish either directly or remotely. The mileage of stream notice- 

 ably affected by the i)olluting wastes is estimated at about 125 

 miles, an ai)i)roximation based U])on the condition of the stream 

 as shown both by oxygen depletion and the presence of biological 

 indicators of pollution. Within this mileage of polluted streams 

 conspicuous examples occur of stream defilement in which the 



