96 THE POPULAR SCIENCE MONTHLY 



lation to fishery problems. Under some conditions a degree of stream 

 pollution may prove distinctly favorable to the abundance of fish: in 

 other cases it is unequivocally injurious. If the matter is one of sig- 

 nificance to the fisheries, it is certainly true, on the other hand, that the 

 problem of stream pollution, in its phases of ordinary interest, can not 

 be studied to a definite conclusion except through analyses of the effects 

 of the pollution upon the living aquatic organisms. This is to say, 

 that the study of the sanitation of our streams involves the investiga- 

 tion of the effects upon fish or upon the organisms constituting the 

 food of fish. 



The dredging of channels and the construction of wing-dams as 

 aids to navigation exert an unmistakable influence upon the distribu- 

 tion of fish and affect the fortunes of their existence in more or less 

 obvious ways. 



The conservation of water upon the farm remains for our considera- 

 tion ; but, if we may be permitted to draw a conclusion at this stage, it 

 is this : — Whether we deal with head-water reservoirs for the regulation 

 of stream flow, with water-power development and the incident pools, 

 with reclamation or irrigation projects, with the dredging and damming 

 for navigation purposes, or with stream pollution by any means, we 

 find a vital relation to fishery problems and to fish-cultural operations. 

 We find also a real necessity for the accumulation of a sufficient store 

 of knowledge regarding the habits of fish, their requirements for feed- 

 ing and breathing and breeding, and how these requirements are af- 

 fected by the conditions that may prevail in our streams, lakes and 

 ponds. We need, in short, an effective fishery science. 



Water Storage and Fish Culture 



We have already expressed the belief that the relation of fishery de- 

 velopment to water conservation is not one of dependence only, but one 

 of reciprocal benefits as well. It must be clear that we are speaking of 

 development, not by protection, but by conservation of fish, with all that 

 the term may imply. The word itself is unavoidably repeated fre- 

 quently in such a discussion, because "conservation" alone seems to 

 embody the whole thought of increase in supply along with development 

 in utilization, as opposed to hoarding or restriction in use. 



Could we think of an agriculture based upon protective measures? 

 Could we imagine a modern nation dependent upon corn and cattle 

 and poultry growing wild? Suppose a series of limitations for the 

 perpetuation of crops and stock-yield, similar to the familiar measures 

 for the preservation of fish or game; no scythe to have a blade more 

 than 3 feet long, no individual to take more than 500 ears of corn per 

 day, or to kill more than 10 pigs or 5 sheep or 2 cows per year. The 

 very suggestion has a touch of absurdity: and yet such is the present 



