82 EEPORT OF THE SECRETARY OF COMMERCE 



products. The system was put into effect immediately in the State 

 and has jjroved satisfactory in the more orderly marketing of these 

 products with benefit to both sellers and buyers. 



The red-snapqjer fishery and industry. — During 1932 a study of the 

 red-snapper fishery and industry revealed that costs of producing 

 red snapper might be lowered by the use of a fish pot which was 

 shown to be very efficient for catching this fish. Also it was found 

 that marketing conditions might be improved by more careful han- 

 dling of the catch aboard vessel to retard deterioration, and by diver- 

 sifying the type of red-snapper product offered for sale. In the latter 

 connection, experiments showed that red snapper lends itself to 

 smoking in the " finnan haddie " style. 



TECHNOLOGICAL INVESTIGATIONS 



Nutritive value of 7narine products. — In cooperation with and in 

 the laboratories of the South Carolina Food Research Commission, 

 Charleston, S.C., the Bureau's technologist completed an investiga- 

 tion in which oysters from different localities were analyzed for their 

 iron, copper, and manganese content, and the dried oysters fed to 

 anemic rats. All samples, regardless of locality from which they 

 were obtained, induced regeneration of hemoglobin, thus giving evi- 

 dence of the importance of oysters as a source of iron in addition to 

 their other food factors. 



Studies on the vitamin potency of salmon-liver oils have revealed 

 that they are from 10 to 12 times as potent in vitamin A as salmon 

 oil from general cannery trimmings. However, since the yield of oil 

 from salmon livers is low and since it requires solvent extraction to 

 obtain the oil from the livers, it is expected that adjustments will 

 need to be effected before placing the manufacture of salmon-liver 

 oil on a commercial basis. 



Further work in cooperation with a producer of kelp meal has 

 shown that kelp meal is a valuable supplement to rations composed 

 of vegetable feedstuffs in which the protein is supplied by plant 

 protein concentrates. 



Preservation of fishery products for food. — Studies on the chemical 

 and physical changes of fresh fish and frozen fish held in cold 

 storage have shown that with improved methods the producers 

 can offer to the public a product superior to those handled by the 

 ordinary commercial procedure. These studies have dealt in detail 

 with the rate of freezing, the temperature of cold storage at which 

 the least change takes place in texture of the flesh, and the rate 

 of change to be expected from fresh fish packed by the usual method 

 in ice. An electrometric method for the determination of the rela- 

 tive freshness of fish flesh also has been developed, which may 

 be of great value in grading fish for quality. Practical experiments 

 in the home preservation of fish by salting and smoking were made 

 before county agentSj home economics experts, fishermen, and house- 

 wives, at various points along the South Atlantic and Gulf coasts. 

 This work has shown that the outlets for fish can be expanded 

 when consumers are acquainted with methods for preserving fish 

 in rather large quantities for family use. 



Bacteriology of fish preservation. — In a study of the bactericidal 

 effect of smoke and salt brining on fish, it has been found that 



