88 REPORT OF THE SECRETARY OF COMMERCE 



of sanitation and prophylaxis against disease in hatcheries and in 

 disseminating such information for practical application in fish 

 hatcheries. 



Cooperative investigations of the nutritional requirements of trout 

 carried on jointly by the New York Conservation Department, 

 Cornell University, and the Bureau of Fisheries at Cortland, N.Y., 

 have progressed satisfactorily where synthetic diets have been em- 

 ployed in testing the vitamin requirements of trout and their ability 

 to digest the various food materials. 



Cooperative trout investigations in the State of California, be- 

 cause of the liberal support afforded by that State, have been 

 continued without curtailment. Ecological studies of the coastal 

 streams and of those in the high Sierras have been undertaken on 

 a large scale to determine the capacity of various waters in sus- 

 taining fish life in relation to the food supply, the physical charac- 

 teristics of the streams, and the drain upon the supply by the fishery 

 as a basis for adequate stocking. 



FISHERY STUDIES IN NATIONAL PARKS AND FORESTS 



As a means of more fully discharging the responsibility of the Fed- 

 eral Government in maintaining the fish supply in the public domain, 

 a survey of streams and lakes in Glacier National Park was com- 

 pleted during the year for the purpose of formulating a stocking 

 policy to be followed in the future. Extensive collections and obser- 

 vations were made and analyzed for the purpose of determining the 

 fish population and the available natural food present as factors in 

 the carrying capacities of various streams. Assistance has been ren- 

 dered various State fish and game departments in the inter-mountain 

 region in solving particular problems regarding the stocking of fish 

 in State waters. 



SHELLFISHERY INVESTIGATIONS 



Investigations on the various problems of the oyster industry were 

 carried out in the North Atlantic and South Atlantic States and on 

 the Pacific coast. In the Northeastern States where previous work 

 of the Bureau has materially aided in increasing the propagation 

 of seed oysters, main effort was directed toward a study of methods 

 of growing and fattening oysters for market and in improving the 

 nutritive quality of the product. Detailed analyses of the glycogen 

 content throughout the year have been made on oysters from 

 the cooperative experimental farms maintained with the State of 

 Connecticut at Milford. In the laboratory at Woods Hole, Mass., 

 and in Washington studies on the growth of natural oyster food give 

 promise of solving the problem of increasing the food value of 

 oysters and standardizing their nutritive qualities. In the South 

 Atlantic, where the depleted state of the natural oyster reefs is most 

 apparent, principal attention was given to methods of restocking 

 and maintaining the productivity of natural and cultivated bottoms. 

 Experimental oyster farms have been maintained in each of the 

 South Atlantic States and extensive surveys in the State of Florida 

 have revealed new areas suitable for oyster culture. On the Pacific 

 coast studies of spawning and improved methods of seed collection 



