90 U. S. BUREAU OF FISHERIES 
First, the drying of the fish; second, a slight cooking; and third, a slightly 
accentuated smoking. The duration of this operation is from 45 to 60 minutes. 
When smoking is completed, each frame is placed horizontally in a special 
apparatus, where a hand-operated triangular knife advances and cuts the heads 
off the fish, which drop on a moving curtain running to the packing tables. The 
heads are removed from the wires and are used for making meal and oil. 
The methods used in other countries are similar to those already 
described. 
AMERICAN DIFFICULTIES 
GENERAL CONSIDERATIONS 
Information as to how to prepare high-quality sardines has not 
been lacking. There are but few canners who do not know how to 
prepare such products. What is needed is information that will 
permit high-quality sardines to be packed cheaply. 
Maine and California sardines for the most part have been pre- 
pared to fill the big demand that exists in the United States and 
elsewhere for cheap sardines. Buyers generally have been more 
interested in price than in quality, provided quality was passably 
fair. This buying practice has led to ruinous competition, in which 
quality frequently has suffered in the race to meet prices. These 
conditions have been more acute in Maine than in California, where 
to some extent canners have been able to rely on by-products for 
profits that they have sacrificed on canned fish. 
The serious effects of this ruinous competition upon the canners 
and the markets for their products are being realized and definite 
steps are now being taken to correct matters. 
American canners undoubtedly will continue to prepare sardines 
largely for the low-price field. Quality, however, will have to be 
considered more important than it has been in the past. Research, 
therefore, should be carried out with the view of furnishing informa- 
tion that will be helpful in producing better sardines at low cost. 
This idea was constantly kept in mind in planning and carrying out 
the research reported upon in this document. A disheartening 
factor faces anyone who plans to carry out research for the sardine- 
canning industry. It may be possible to produce helpful informa- 
tion only to find that it is not used to improve quality but rather to 
lower prices still further. If quality is overlooked and competition 
for quantity production at the lowest cost continues as strong as it 
has in the past, this will happen. 
TECHNOLOGICAL CONSIDERATIONS 
The production of good-quality sardines depends upon a few 
well-defined factors: (1) the quality of the fish themselves, inelud- 
ing their condition, handling, and cleaning; (2) the preparation of 
the fish for canning; (3) the materials placed in the can with the fish; 
(4) the canning procedure itself; and (5) the chemical and physical 
changes that take place within the can during processing and later 
storage. 
It was decided at the start of the investigation that the field covered 
by (2)—the preparation of the fish for canning—offered the greatest 
opportunities for research. The publication by Weber (see footnote, 
p. 72) on the Maine sardine industry was the only report of scientific 

