GENERAL LOSSES BY STREAM POLLUTION 



The value of the individual water body is not always apparent and 

 the significance of the destruction wrought by eliminating the life 

 from it frequently appears only after a careful analysis of the situa- 

 tion. It is not possible within the limits of this report to do more 

 than indicate some phases of the argument on this question, but they 

 will serve to suggest other particulars and to demonstrate clearly 

 the need of careful study that the public may not suffer unrecognized 

 losses of a serious character which it may be difficult to make good. 

 In any case, it is expensive in time and money to restore a stream 

 to its original condition. Individual examples of particular factors 

 in the problem may be cited here. 



Value of Small Streams 



The small streams which empty into lakes or constitute the side 

 branches of larger river systems are in a sense insignificant. Their 

 area is trivial, the amount of water they carry is not large, and, from 

 any standpoint, one might think the destruction of living conditions 

 within them to be of little moment for the general welfare. But 

 such places are, in the first instance, breeding grounds for the larger 

 fish. At some period of the year, and often at several such for 

 different species, fish migrate into the smaller and shallower waters, 

 deposit their eggs and return to the larger environment. Unless one 

 has studied the streams carefully, he may be entirely unacquainted 

 with the fact of this relation, for while all know the movements of 

 the larger fish, which, like shad or salmon, migrate in enormous 

 schools to their spawning grounds, yet men do not recognize, gener- 

 ally, the movements of other species which go more irregularly or 

 in smaller groups, and traverse shorter distances* Now, whatever 

 renders the stream barren and incapable of supporting life eliminates 

 it from functioning as a spawning ground, and it requires little 

 reflection to see that the destruction of spawning areas limits or 

 ultimately terminates the reproductive activities of the species and 

 will be followed by the extermination of the fish. Indeed, there is 

 no doubt that the marked reduction in the numbers of adult fish in 

 many regions is directly traceable to the destruction of spawning 

 grounds, or to the presence of conditions which if not fatal are very 

 unfavorable to the young in the egg or fry stage when they are so 

 susceptible to injurious influences. 



