BUREAU OF FISHERIES 97 



Nutritive value of aquatic 'products. — Studies in this connection 

 have inchided determination of the vitamin potency of various fish- 

 liver oils, of the development of menhaden fish oil for poultry feed, 

 menhaden fish meal in cattle feed, studies of the nutritive value of 

 mackerel, the biological value and digestibility of fish proteins, and 

 studies of the mineral constituents in fishery products. Publications 

 have been issued on these various products. 



Fish cookery. — Work in fish cookery has consisted in the develop- 

 ment and testing of a variety of recipes for preparing fish and shell- 

 fish. There is a great need for work in this field as the average 

 housewife knows little concerning the possible varieties in the cooking 

 of fishery products. A new cook book, published by the Bureau 

 about a year ago, proved very popular and over 60,000 copies of this 

 publication have been distributed, in cooperation with the fishery 

 industry. 



BIOLOGICAL riSHEBY INVESTIGATIONS 



Biological investigations of the fishery resources form the founda- 

 tion of all conservation policies and recommendations of the Bu- 

 reau of Fisheries. When the Bureau was first established, such in- 

 vestigations to discover the conditions and trend of the important 

 fisheries, the causes for a decline in the supply of some which 

 had been noted, and the devising of corrective measures were the sole 

 functions of the organization ; and these activities still constitute one 

 of the most important branches of its work. During recent years 

 investigations, organized on a continuing basis, are concerned pri- 

 marily with (1) the tracing or foretelling of natural fluctuations 

 in abundance of the important commercial species, (2) the manage- 

 ment of interior waters including the stocking of lakes and streams 

 with the most desirable food and game fishes at a rate consistent 

 with the productive capacity of the various waters, with environ- 

 mental control to increase productive capacity and with regulation 

 of the catch to assure maximum production, and (3) the development 

 of modern methods of water farming as applied to the shellfish 

 industry. 



INVESTIGATIONS OF COMMERCIAL FISHES 



North anid Middle Atlantic fishery investigations. — In the North 

 and Middle Atlantic, haddock, mackerel, squeteague or weakfish, 

 and the flounder, scup, sea bass, and related species taken in the 

 shore fishery and in the Southern winter trawl fishery, are the sub- 

 ject of study. With the upturn of fish prices during 1935, activity 

 in the fishing business in the North Atlantic section has reawakened. 

 Vessels tied up during the previous years have been placed in service 

 and new ones are being built, while the efficiency of smaller vessels 

 has been increased by additional motorization. Species hitherto 

 neglected or regarded as trash fish, such as the rosefish and the 

 sea robin, are being marketed in rapidly increasing quantities. 



Observations on the condition of the resource during the past year 

 indicate that the supply of haddock, the most valuable and impor- 

 tant species in the North Atlantic fishery, generally remains low as 

 compared with the abundance prevailing 10 to 15 years ago, although 

 the stock of Georges Bank and of the South Channel, which are the 

 most productive grounds, apparently has increased somewhat over 



