334 XJ. S. BUKEAU OF FISHERIES 



gation, where such is necessary to supplement natural propagation; 

 the protection of downstream migrants from loss in irrigation works 

 and at power dams ; and the prevention of stream pollution. A com- 

 petent staff has made a satisfactory beginning in this great under- 

 taking, and if the management of the resource is based upon con- 

 tinued scientific studies we may be assured of its permanent 

 productiveness. 



The third branch of activity of the Division is concerned with the 

 shellfish industry. Oysters are the most valuable single marine prod- 

 uct and are the most susceptible to cultivation and management. The 

 Bureau has assisted in continuing improvements in oyster farming, 

 but there remains a vast field for service in directing oyster planting 

 as a means of public relief and as conservation of the resources. 

 Technical control and experiment are still required, 



COOPERATIVE INVESTIGATIONS 



For many years the Bureau has had valuable informal cooperation 

 in fishery investigations from many institutions, both public and 

 private, but the acceptance of formal cooperation was not legally 

 authorized until the passage of an act of Congress approved May 21, 

 1930. The Bureau's program has always been closely correlated with 

 work of various bureaus of the Department of Commerce from which 

 it secures assistance of various kinds, chiefly relating to the promotive 

 aspects of commercial fishery investigations. During the past year 

 closer cooperation has been established with the United States Forest 

 Service and the Bureau of Biological Survey of the Department of 

 Agriculture, in relation to the development of fisheries of interior 

 waters. 



Reference has been made to fishery investigations conducted by the 

 States. California has continued with the Bureau its cooperative 

 investigations concerned with the trout supply, looking toward secur- 

 ing a more adequate supply of fish in streams and the more rational 

 regulation of fishing within its borders. New York State has con- 

 tinued its cooperation in the conduct of studies of the nutritional 

 requirements of trout to improve hatchery practices in feeding and 

 rearing. Oregon has cooperated with a Bureau investigator in a 

 study of fish diseases and hatchery practices. North Carolina. Con- 

 necticut, and Washington have assisted in investigations for the 

 restoration of oyster beds in their coastal waters, and Georgia, Louisi- 

 ana, and Texas have taken an active part in the study of the impor- 

 tant shrimp fisheries investigations of the South Atlantic and Gulf 

 coast. Despite the fact that State budgets have been reduced propor- 

 tional to Federal budgets for these projects, this cooperation has been 

 very effective and is greatly appreciated. 



Another source of most valuable cooperation is provided by educa- 

 tional institutions, chiefly universities. Laboratory quarters for the 

 Bureau's investigative staffs are provided by Harvard LTniversity as 

 headquarters for North and Middle Atlantic fishery investigations, 

 the University of Michigan as headquarters for the Great Lakes 

 fishery investigations, the University of Utah for fishery investiga- 

 tions in the intermountain section, University of Missouri for investi- 

 gation of interior waters, and Stanford Universit}?^ for California 



