FISHERY INDUSTRIES OF THE UNITED STATES. 13 



to the proper degree of fineness and to break up any small, sharp- 

 pointed bones or spines. This was found necessary for menhaden 

 meal. The most practical type of grinder for breaking up such bones 

 appears to be the swdng-hammer type, in which swinging hammers 

 revolving at about from 2,500 to 3,000 revolutions per minute knock 

 the material against a screen. 



As evidence of the results of the Bureau's efforts, it may be added 

 that in the menhaden and shrimp industries about 2,500 tons of 

 meal were produced in 1919 and no difficulties in marketing it at 

 reasonable prices reported. It is believed that the present annual 

 production of meal from fishers^ products approximatmg 10,000 tons 

 may be doubled without difficulty and with improvements which 

 will keep menhaden fresh until they reach the factory at least 

 trebled. It may be noted that a classification for fish meal is in 

 effect in the three classification territories of the railway companies, 

 and class rates on this commodity between given points ai'e obtainable 

 by application to the proper railroad officials. 



FISH LEATHER. 



The work of the Bureau in (>neouraging the development of a fish- 

 leather industry has resulted in important progi'css in this field. The 

 tanning of the hides of sharks and rays into leather wliich is soft and 

 pliable and of ample strength for many uses is now an established 

 fact, and keen interest is being shown in the development of fisheries 

 for these forms to make available regular supplies of basic materials 

 in quantity production. The use of the liides of porpoises, whales; 

 sea lions, and other unutilized aquatic animals is also increasing. 

 One tannery is now devoted to the production of fish leather, a 

 second is in course of construction, and others are preparing to engage 

 in the industry-. 



SHARK FINS. 



The Bureau has been instrum<>ntal in th(> saving and drv'ing of 

 shark fins, which are a deUcacy highly prized by orientals. In one 

 city in this country the demand now exceeds the supply, the best 

 grades commanding from 65 to 75 cents per pound. 



The trade is furnished with descriptive matter for the preparation 

 of the various bv-products, oils, scrap, meal, hides for the tanner, 

 and fins, and witli information as to where the various commodities 

 may be marketed. 



TECHNOLOGICAL INVESTIGATIONS. 



In the 1018 report attention was called to the construction and 

 equipment of a fishery Profhicts Laboratory in Washington for the 

 concluct of technological investigations in the fisheries. Although 

 its activities have been greatly restricted by the limited personn(>l 

 and provision for the work, the results achieved in the investigations 

 regarding the salting of fish, the studies of fish oils, recovery of used 

 brine and salt, preliminary studies of the production oi essence 

 d'Orient from fish scales, and the different methods of refrigeration, 

 the; direction of the investigations in the canning of fish in southern 

 California, and provision for the proper handling of minor problems, 

 have emphasized the need for the conduct of such work on a larger 



