316 U.S. BUREAU OF FISHERIES 



ing to serious pollution of our streams. This is a new attack by 

 newly perfected methods upon the pollution problem from an en- 

 tirely different angle than heretofore undertaken and if successful 

 may make possible the adoption on a large scale of simplified methods 

 of sewage treatment. 



3. Construction of fish screens in the Pacific Northwest by Public 

 Works funds to prevent the destruction of downstream migrating 

 salmon and other food fishes by irrigation works on Government 

 })roperties such as reclamation projects or Indian reservations. 



4. Investigation of the requirements for fish-protective works at 

 the various hydroelectric, irrigation, and navigation dams on the 

 Columbia River. This project has been financed by the Public 

 Works Administration for a study of fishways and other protective 

 works at the Bonneville (Oreg.) Dam and should be extended to 

 the Rock Island and Grand Coulee Dams. 



Much of this work will not actually be undertaken until the spring 

 and summer of 1934. Hence, reports of these activities will be pre- 

 sented in the next annual report of this Division. 



STATE COOPERATION 



The biological investigations of the Bureau, forming as they do 

 the very foundation of the conservation efforts of the States, have 

 always received liberal support and in many cases active coopera- 

 tion from the State fish and game departments. The Bureau's 

 investigations, conducted on the highest scientific plane, are always 

 regarded as disinterested and authoritative, and, hence, exert a very 

 real influence on the trend of thought in conservation circles and on 

 local legislation. 



Because of the tremendous field to be covered and the relative in- 

 adequacy of financial support, the projects for scientific investiga- 

 tion are necessarily chosen because of their wide and general ap- 

 plicability in the protection and development of the fishery resources, 

 and hence local problems frequently remain unsolved for many 

 years. For example, attention is first given to those great commercial 

 fisheries of importance over wide areas for the purpose of deter- 

 mining their trend and present condition either as a guide to their 

 regulation or as a guide to industry in the better utilization of the 

 annual harvests and in avoiding disastrous gluts or famines in the 

 market. 



In determining the changes in relative abundance from year to 

 year of the total supply of species supporting a great fishery, prob- 

 lems of local management arise, which, under the circumstances, 

 must be neglected by the Federal Government and must remain 

 unsolved unless the State Governments are able and willing to co- 

 operate in determining the conditions that affect their local fishery. 

 On the Atlantic coast of the United States, for example, the abun- 

 dance of fish in any of the bays or channels of Long Island or New 

 Jersey, or even in Chesapeake Bay, are largely determined by the 

 variations in abundance in the main stock of fish in the offshore 

 waters. The Bureau's investigations have shown that the weakfish, 

 the scup, the flounder, and the bluefish all migi'ate extensively over 

 the area from the Carolinas to Cape Cod, and that the spawning 

 areas for most of these species lie chiefly in southern waters. Hence, 



