BUREAU OF FISHERIES 109 



units as compared to the minimum requirements for cod-liver oil of 

 600 vitamin A units and 95 vitamin D units. Besides <;ivin«5 added 

 revenue to the lishin<!; industry, these studies contributed to the 

 domestic supply of vitamin-bearin<T materials. 



Nutritive value of aquatic products. — Studies of the nutritive 

 value of aquatic products during the past year included a determina- 

 tion of the vitamin content of swordfish-liver oils, sahnon oils, and 

 other fish ajid fish-liver oils extracted according to various experi- 

 mental methods as previously discussed ; a determination of vitamins 

 A and G in crab meat, a study of the food value of sodium alginate, 

 analyses of conch meat; and data on the role of the mineral con- 

 stituents of fishery products in nutrition. In making these studies, 

 our technologists made use of chemical methods and practical feed- 

 ing tests wiith laboratory animals as well as biological tests with 

 human subjects. Our investigations reveal that fish oils and fish- 

 liver oils are of great potential sources of vitamins for both human 

 and animal nutrition; that crab meat is a relatively good source of 

 vitamins A and G; tliat sodium alginate is not only of value as a 

 stabilizer in the preparation of dairy products, but that it has food 

 value comparable to the kelp from which it is made; and that the 

 mineral constituents found in fishery products and byproducts are 

 of great importance in human and animal nutrition. 



Fish cookery investigation.^. — During the past year, the Bureau 

 established a fish cookery laboratory and developed by actual tests 

 simple and practical recipes for the preparation and cooking of fish 

 and shellfish. A very popular publication on practical fish cookery 

 was issued and widely distributed by the Bureau, based on these 

 recipes. 



BLACK BASS AND ANGLEBS DIVISION 



The black-bass law was enforced by 2 regular field officers, 1 or 2 

 temporary employees, 1 permanent employee in the Washington 

 office, and approximately 100 deputy black-bass-law inspectors who 

 are regularly employed State fish and game protectors, and who 

 serve the Federal Government without paj' under the direction of 

 the Chief of the Division. Several violations of the Federal black- 

 bass law w^ere found, but in only one instance was it necessary to 

 report the case for prosecution in Federal court. Active field work 

 has been conducted in well-known black-bass areas east of the Rocky 

 Mountains, and fish markets of the principal cities have been 

 inspected for illegal shipments. The Division receives the hearty 

 cooperation of all tlie State authorities in those States where it 

 functions. 



During the year the legislatures of 44 States met in regular ses- 

 sion, afl'ording an opportunity to obtain much needed State legisla- 

 tion protecting black bass, without which the Federal law cannot 

 be fully effective. Three States passed laws prohibiting the sale of 

 black bass at all times, regardless of where taken, making a total of 

 37 States where these game fish are afforded this means of protection. 

 One State adopted a closed season, leaving but 7 States that do not 

 BOW protect the bass on the nest during at least a part of the spawn- 

 ing period. The closed season was also extended in several States. 



Several States increased the size limit or decreased the daily limit 

 on black bass; 6 States adopted a commission fonn of administering 



