VI REPORT OF THE COMMISSIONER OF FISHERIES 



In the report for 1924 mention was made of the development and 

 successful operation on small and semicommercial scale of a new 

 process of preparing fish for canning as sardines, originated in the 

 bureau's experimental laboratory at San Pedro, Calif. Since then 

 experiments have been carried out in Maine. The same process was 

 successfully applied to the preparation of Maine sardines. 



UTILIZATION or 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 w^aste and the residue made into fish 

 meal. These products are very valuable ; the oil is used for making 

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

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

 Although a great deal has been accomplished in the matter of 

 eliminating waste, much yet remains to be done. Less than half of 

 the supply of waste products of the fisheries is now being utilized, 

 and present practices of manufacturing fish meal and oil, both from 

 offal and from nonedible fish, are in general quite inefficient. There 

 are also possibilities for producing better and more valuable prod- 

 ucts. The bureau is especially interested in these problems, since 

 any improvement which may be brought about, either through edu- 

 cation or by research, will increase the prosperity of the fisheries 

 industries and contribute to national economy. 



Some phases of this problem are of particular importance at this 

 time. Methods should be developed to either eliminate the press 

 liquors or economically recover and utilize the protein matter that 

 is present in them and now discarded. This material not only 

 constitutes a great waste, but it seriously pollutes our coastal waters 

 in some localities. Small inexpensive plants are needed to handle 

 small quantities of offal, such as collect at many places, as w^ell as 

 equipment capable of handling profitably large quantities of mate- 

 rial for a period of four to six weeks in each year. At present 

 operations are profitable only when large amounts of fish or offal are 

 utilized and operations are continued over a good part of the year. 

 Research is now being conducted along these lines. 



PRESERVATION OF NETS 



Very good reports are being received concerning the use of copper 

 oleate as a net preservative. It is proving particularly effective on 

 pound nets, especially in combination wath copper paint. On the 

 coasts of Long Island and New Jersey tarred netting ordinarily 

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

 month during part of the season in order to remove hydroids, 

 barnacles, and other marine growths. With the antifouling copper 

 oleate-copper paint mixture it is only necessary to remove the net- 

 ting for treatment about every two months. Under such conditions 

 it is proving profitable to use this mixture on pound nets, the twine 

 of which costs about $4,000 per net. 



The full value of copper oleate as a net preservative can not be 

 demonstrated accurately until data are available upon the compara- 

 tive costs of treating netting with various preservatives and the 



