PROGRESS IN BIOLOGICAL INQUIRIES, 1935 447 



FISHERY INVESTIGATIONS IN INTERIOR WATERS 



M. INI. EtLis, in cliurije 



POIJATTION STUDIES 



The growing menace of pollution in tlie fresli -waters of the United 

 States by erosion, and by municipal and industrial wastes has been 

 accepted fatalistically by many as inevitable because the basic facts, 

 chemical, physical, and biological, concerning stream pollution gen- 

 erally have not been available. The menace is spreading not only 

 throughout the various river systems but into the impounded waters 

 as well, and threatens at various points the waters of the public 

 domain and of the national ])laygrounds. Consequently remedial 

 and corrective measures compatible with the interests of fisheries and 

 with economic necessities have not been easy to define. 



To meet this situation the Columbia (Mo.) field unit of the United 

 States Bureau of Fisheries has been conducting for some time in- 

 vestigations to ascertain: (1) The natural conditions favorable for 

 fish and other aquatic life in unpolluted waters, so that a polluted 

 stream can be defined with fairness to all concerned; (2) the specific 

 effects on fish and other aquatic life, and on the aquatic environment 

 itself, of the various types of effluents which are being turned into 

 the fresh waters of the United States. 



Much effort has been given to devising suitable tests for the de- 

 termination of the extent of stream pollution that could be applied 

 practically in the field. 



A set of water standards has been defined, based u]5on the results 

 of thousands of tests and analyses made in all of the major river 

 systems of the United States. The connnon variables in stream 

 water; namely, dissolved gases, salts, turbidity, and ammonia are 

 defined vritli reference to the limits constituting a suitable environ- 

 ment in which desii-able fish can thrive. These standards provide a 

 background for the study of stream pollution regardless of its source 

 or extent. 



Detailed biochemical, physiological, and pharmacological studies of 

 over 40 types of effluents have been made, from Avhich the specific 

 effects of these effluents on fish and other aquatic life, as well as the 

 reactions of these effluents Avith the stream water itself have been 

 determined. From these studies it lias been possible to make definite 

 recommeudations for practical remedial measures in various cases of 

 stream pollution. As this work is continued more such applications 

 can be made. 



Mobile units, housed in autotrucks, have been perfected for the 

 field study of stream pollution. These field laboratories make it pos- 

 sible to cover large distances rapidly, and to obtain at the source 

 of pollution data supplementing the experimental tests con- 

 ducted at the central laboratory at Columbia, ]Mo., and at tlie branch 

 laboratories for trout studies at Bozeman, Mont., and for long-time 

 tests on warm-water fishes at Fort Worth, Tex. 



During t\\Q past year, in addition to the general work outlined 

 above, specific pollution investigations have been made in Maine, 

 Pennsylvania, West Virginia, Tennessee, South Carolina, Virginia, 

 Montana, Idaho, Arizona, New Mexico, Texas, Oklahoma, and in the 

 Mississippi Valley, through cooperation with the War Department, 



