186 "U- S. BUREAU OF FISHERIES 



quality. At the present time only a relatively small part of the 

 catch of haddock and cod is made close to shore, and for this reason 

 the method may find use as a temporary means of preservation for 

 the livers yielded by the fisheries for these species. 



During 1937 one of the research associates working on the chemical 

 preservation of fish waste was stationed at Boston, Mass., to direct 

 the handling and preservation of fish livers at sea. Under his direc- 

 tion many types of chemical preservatives were tested under practical 

 conditions. The preservative solutions were sent to sea on fishing 

 vessels and fresh livers were placed in these solutions by the fishermen. 

 The livers were then shipped to the Bureau's College Park laborato- 

 ries, where they were inspected, rendered, and the relative quality of 

 the oils determined. By these experiments there was developed a 

 very effective preservative chemical solution which stopped bacterial 

 and enzymatic decomposition and kept the oils in their original fresh 

 condition. However, rendering methods in ordinary commercial use 

 were not easily adapted to these preserved livers. Therefore, a new 

 "flotation" process was developed which results in high yields of oil, 

 oils of high quality, and economy of operation. The details for large 

 scale application for these preservative and rendering processes are 

 now worked out on a semicommercial basis and the commercial 

 usefulness of the work seems assured. 



As a part of this cooperative program our nutrition laboratory is 

 making an extensive study of the vitamin A and D content of the 

 various organs of the viscera of cod, cusk, hake, halibut, haddock, 

 pollock, and other species preserved with the chemical formulas. 



NUTRITIVE VALUE OF AQUATIC PRODUCTS 



There is a great need for more complete information concerning the 

 food value of various commercially important fishery products. There 

 is also considerable demand for this information, not only from the 

 industry, but from the consuming public. There are notable gaps in 

 this information because scientific studies have not covered all of 

 these fishery products, and there is only partial knowledge of the 

 nutritional properties of some of the others. The lack of this informa- 

 tion liinders dietitians and home economics experts in determining the 

 most satisfactory use of fishery products in the diet. The food and 

 drug industries need, and have requested, information on the nutritive 

 value of aquatic products. The feed manufacturer and the farmer 

 require more complete data on the qualities of fishery products for 

 animal feeding. Therefore, it is highly important that our techno- 

 logical staff obtain, as soon as possible, more complete information 

 on this subject, and at least fill in the important gaps in scientific 

 knowledge concerning the unexcelled nutritional value of these prod- 

 ucts of the sea. 



Furthermore, nutrition studies are necessary to properly evaluate 

 our technological investigations on the improvement of existing 

 methods and the design of new methods in the handling, utilization, 

 processing, preservation, and storage of the great diversity of prod- 

 ucts of the fishery industries. 



During 1937 investigations concerning the nutritive value of fishery 

 products and byproducts were conducted in our College Park labora- 

 tories under the supervision of James M. Lemon, technologist in charge, 



