764 MARINE PRODUCTS OF COMMERCE 



By-products 



The field of fishery by-products, particularly fish meal and oils, has already 

 been extensively investigated. Undoubtedly much more can be done in this field. 

 For instance, many fish oils, vv^hich at the moment are used for technical pur- 

 poses, contain appreciable amounts of vitamins which are destroyed in the fur- 

 ther chemical treatment of the oils. It is not unlikely that research would find 

 methods by which these vitamins could economically be separated from the oils. 



When considering the field of fish meal and oil it is necessary to realize that 

 there are at the moment very considerable quantities of valuable fish proteins 

 which are used for fish meal (i.e., mainly for feedstuffs for domestic animals). 

 This is, of course, an excellent way of utilizing these proteins which come mainly 

 from waste products, ofi^al, or from less palatable fish of little commercial value. 

 Through the utilization as feedstuffs they are eventually turned into high quahty 

 foods; but the yield is low. As a rule it is difficult to recover more than 20 per 

 cent of the original food value of the proteins. From a purely nutritional stand- 

 point it would therefore be better to use such proteins directly for food. They 

 must be first made acceptable and usable in some form. This might be done by 

 purifying the proteins, as has been done for many years in Germany, where such 

 proteins were used as egg-white substitutes. These proteins might also be used 

 in a somewhat less purified form in bread. Experiments in Norway have shovvTi 

 that up to 6 per cent of such fish flour can be added to bread without any objec- 

 tionable effects, thereby highly improving the nutritional value of bread. 



Utilization of Plankton 



The amount of plankton in the oceans is of a far greater magnitude than that 

 of all larger animals or plants. This plankton is highly nutritional, and it has been 

 found that the high content of certain vitamins in cod-liver oil is not synthesized 

 in the cod itself but can be traced back to the vitamin content in certain plankton 

 diatoms. Thus, if one could find ways of utilizing the plankton resources directly, 

 the food production from the sea could be multiplied a great many times. German 

 scientists have already proved that edible fats can be manufactured from plankton, 

 and experiments have shown that plankton can be used directly for food. Any 

 commercial application still seems to be in the future, not only as a result of 

 diflBculties of manufacturing suitable food products from plankton, but also due 

 to the difficulties of designing methods for the collection of this material. How- 

 ever, such possibilities which may contain promises for entirely new and im- 

 portant commercial products should be recognized. 



REFERENCES 



Anon., "Research Goes to Sea," Cambridge, Mass., Arthur D. Little, Inc., Industrial Bull., 



256 (1949). 

 Anon., "Utilization of Alaskan Salmon Cannery Waste," Pts. I and II, U. S. Department of 



Commerce, Office of Technical Services ( 1947-1948 ) . 

 Anon., "Protamin from Salmon Milt of Medicinal Value," Pacific Fishennan, 34, No. 7, 



29 (1936). 

 Anon., "Large Development in Fishery By-products Seen," Fishing Netcs, 33, No. 1675, 



19 (1945). 

 Beall, D., "EflBuent Losses at Pilchard Reduction Plants," Fisheries Research Board 



Canada, Prog. Repts., Pacific Coast Stations, 20, 14 (1934). 



