332 U. S. BUREAU OF FISHEEIES 



Page 



Investigations on aquiculture 380 



Pondfish culture 381 



Trout culture 382 



Fish diseases 389 



Stream survey and stream improvement 391 



Stream improvement in connection with stream surveys 392 



Investigations in the Rocky Mountain regions in the interest of fish 



stocking 392 



Cooperation with the Forest Service in stream and lake improvement- 394 



Cooperation with the University of Utah 395 



Investigations in interior waters 395 



Pollution studies 395 



Power dam lakes and other impounded waters 396 



Mussel propagation 397 



Independent activities of the Fisheries biological laboratories 397 



Woods Hole, Mass 397 



Beaufort laboratory 397 



INTRODUCTION 



The United States Bureau of Fisheries is the only Federal agency 

 conducting research looking toward the development and conserva- 

 tion of the fishery resources in the United States. The major portion 

 of research on conservation problems is conducted by the Division 

 of Scientific Inquiry, for technological research is mainly promo- 

 tive and contributes only indirectly to a solution of the problems 

 ■of conservation by promoting a fuller use of fishery products. As 

 a general rule, the State governments do not have facilities nor 

 resources for the conduct of fishery research on an extensive scale. 

 Many States, however, contribute to or cooperate effectively in work 

 conducted by the United States Bureau of Fisheries. 



The technical staff of the Division of Scientific Inquiry numbers 

 45 trained experts, with perhaps an equal number of temporary 

 assistants at some time of the year, but the problems of the fisheries 

 are as numerous as the species that are exploited. Some 30 important 

 food and game fishes are the subjects of continuing research. To 

 give adequate attention to the fisheries in all sections of the United 

 States, both coastal and interior, and in Alaska, at least double this 

 number of investigators would be required. 



The aim of fishery investigations is to determine which species 

 are showing depletion as a result of man's exploitation, what methods 

 may be applied tow\ard their conservation through the management 

 of supplies on the basis of sustained yield, and the development of 

 improved methods of cultivating aquatic animals. From a scientific 

 standpoint research is conducted in the various fields of applied sci- 

 ences, including fishery biology and aquiculture, and in the funda- 

 mental sciences of ecology, oceanography, limnology, physiology, 

 systematic ichthyology, and biostatistics. Research projects during 

 the past year were organized imder three major branches: (1) Com- 

 mercial fishery investigations in marine and fresh waters; (2) aqui- 

 cultural investigations, including improvements in the propagation 

 of fresh-water fish and the study of aquatic environments and pol- 

 lution control; and (3) shellfishery investigations for the develop- 

 ment of oyster farming and the control of sliellfish pests. These 

 projects are organized under seven distinct sections, each directed 



