FISHERY INDUSTEIES OF THE UNITED STATES, 1924 223 



of the process on a large scale must be formulated which will eliminate 

 most of the risk to the canners. This phase of the problem is now 

 receiving consideration. 



UTILIZATION OF BY-PRODUCTS 



Considerable progress has been made in the last few years in the 

 utilization of the large quantities of waste fish and offal from fish 

 markets and concerns manufacturing preserved products. Oil can 

 be extracted from most fish waste and the residue made into fish 

 meal. These products are very valuable. The oil is used in making 

 soaps, paints, m tanning leather, and for many other purposes, and 

 the meal serves as a stock and poultry food and as a fertilizer. 

 Although considerable has been accomplished in eliminating waste, 

 much yet remains to be done. Less than half the supply of waste 

 products of the fisheries is now being utilized, and present practices 

 of manufacturing fish meal and oil, both from ofi'al and from non- 

 edible fish, are in general quite inefficient. There are also possi- 

 bilities for producing better and more valuable products. The bureau 

 is especially interested in these problems, as any improvement which 

 can be brought, either through education or by research, increases the 

 prosperity of the fisheries industries and contributes to national 

 economy. 



Some phases of this problem are of particular importance at this 

 time. Ways should be developed of either eliminating the press 

 liquors or of economically recovering and utilizing the protein matter 

 which is present in these liquors and now discarded. This material 

 is not only a large waste but it seriously pollutes our coastal waters 

 in some places. There is need for small, inexpensive plants to handle 

 small quantities of offal, such as collect in many places, and for equip- 

 ment to handle profitably large quantities of material for a period 

 of 4 to 6 weeks of each year. At present it only pays to handle 

 relatively large amounts of fish or offal where operation can be con- 

 tinuous over a good part of the year. Research is now being 

 conducted along these lines. 



PRESERVATION OF NETS 



Many very good reports are being received concerning the use of 

 copper oleate as a net preservative. It is proving particularly effec- 

 tive on pound nets, especially in combination with copper paint. On 

 the coasts of Long Island and New Jersey tarred netting ordinarily 

 lasts but two season and has to be taken from the water about twice 

 a month during part of the season in order that hydroids, barnacles, 

 and other growths may be removed. Where the copper oleate- 

 copper paint mixture is used it is only necessary to remove the 

 netting for treatment about every two months, there being no 

 growth. Under such conditions with the twine in a pound net cost- 

 ing around S4,000 for each net it is proving very profitable to use this 

 mixture. 



Unfavorable reports also are received, and in many cases fishermen 

 who started to use copper oleate have gone back to old methods of 

 preserving their twine. Copper oleate may be applied improperly or 

 used for a purpose for which it was not intended, and cases of dis- 



