754 MARINE PRODUCTS OF COMMERCE 



the flesh. Research could develop methods for the treatment of this protein so 

 that it could be stabilized, and thus increase the demand for shark meat. 



There is an abundance of carp (Cyprmus carpio) available in all the fresh- 

 water lakes and streams of the Midwest. These fish are considered a nuisance and 

 are seined out to make room for the more desirable species. Little use is made 

 of those thus destroyed. One small cannery attempted to pack them as carmed "fish 

 flakes" in the last years of World War II. Insufficient study and research was given 

 to the preparation of this product, and a ready market has been difficult to find. 

 A sizable market could probably be developed if the technique of preparation and 

 process were perfected. As an alternative, while these fish contain only small 

 amounts of oil, the protein is highly valuable, and they could be reduced to fish 

 meal which would find a ready market. 



These are only a few illustrations of problems in the field of marketing new 

 species of fish. There are many other species of fish little utilized at present 

 because of unfounded prejudice against them. One of the reasons for this is the 

 lack of widespread advertising which would familiarize the public with the quali- 

 ties of these fish. It is only since World War II that home economists of the Fish 

 and Wildlife Service have conducted cookery demonstrations. Popular in pubhc 

 school lunchrooms and before groups of housewives, these demonstrations should 

 be given on a far larger scale. 



Utilization of Fish Livers 



The problem of supply and demand for fish-liver oils of high vitamin A potency 

 has, to a large extent, been solved. However, many processes for the recovery of 

 vitamin A are inefficient and in need of improvement. Many of the fish livers used 

 in the production of this vitamin contain only small quantities of oil. Vitamin A is 

 combined with the protein of the liver so that the recovery requires the destruc- 

 tion of the protein molecule. After the vitamin has been removed, the remaining 

 material, which contains partiallv digested protein, is discarded. Research into 

 possible methods for the recoverv and utilization of these waste products would 

 probably lead to the establishment of an entirely new industry, which would be 

 beneficial to both fishermen and processor. 



Most of the processes used for the recovery of vitamin A from fish livers do 

 not remove the last traces. Research is under way to increase the eflBciencv of 

 these methods. 



There is concern among the processors of fish livers over the possibihty of the 

 loss of their markets through competition from the new less expensive synthetic 

 vitamin A. It would be well worth-while for them to have studies made of the rela- 

 tive therapeutic values of the natural and synthetic vitamin A; as yet, this has 

 been done only to a limited extent. It is possible that deficiencies in the synthetic 

 product may more than offset its lower cost to the consumer. 



There is a considerable demand for bile acids for the production of various 

 pharmaceuticals. The fish livers do not contain large quantities of this material, 

 but gall bladders have to be removed from the livers before they are packed for 

 the vitamin A processor. If these were preserved in a separate container instead 

 of being thrown overboard, thev could add to the income of the fishermen when 

 sold to the producers of these acids. There is a market for these if they are han- 

 dled carefully and are well-preserved prior to sale. 



