18 , BULLETIN 150, U. S. DEPARTMENT OF AGRICULTURE. 
CHARACTER OF WASTE. 
The first waste involved in the canning of salmon to be considered 
in this discussion is the waste of fish other than salmon taken with 
them in seines and traps. This varies widely from day to day and 
with the place and method of fishing. At best it is a matter of great 
uncertainty. Thus, in a scow load of 30,000 salmon taken from a trap 
under the observation of the writer, there was an entirely negligible 
number of fish other than salmon, while from another trap it was 
recorded that the catch was made up of approximately 50 per cent 
of salmon and 50 per cent of other fish. Of the salmon about 1 per 
cent was dog salmon, a slightly larger proportion was humpbacks, 
i0 per cent was echoes, and the balance, about 88 per cent, was sock- 
eyes. Among the other fish taken, a number equal to that of the 
salmon, were trout, tomcocl, flounders, and dog fish. Where the pro- 
portion of fish other than salmon taken in traps is so great, they are 
thrown from the scow as fast as br ailed into it ; while if the propor- 
tion be small, they are permitted to remain. When the fish are un- 
loaded at the cannery these are thrown overboard by the unloaders as 
encountered, or, frequently, the edible fish are picked out by children 
or adults from among the laborers around the cannery and are 
used for food. Aside from the fish so consumed, there is a consider- 
able number of food fish 'for which there is no demand, as well as 
nonedible fish, such as dogfish, which easily could be made available 
as a supplementary source of material from, which to prepare ferti- 
lizer and oil. However, from the casual observations of a summer 
spent in and around the salmon canneries and from the answers to 
casual inquiries regarding the matter, it must be said that as a 
source of such material the fish other than salmon, taken incidentally 
in the. salmon fisheries, are too uncertain and too variable in amount 
to be given very serious consideration. Undoubtedly, in the aggre- 
gate they form a considerable supply, and a large part of it could 
be made available for fertilizer manufacture. But in view of the 
many elements of uncertainty involved, it perhaps is unnecessary to 
speculate further upon the bearing of this supply on the problem 
under discussion. 
In the neighborhood of some of the canneries to-day, where the 
waste from the dressed salmon is thrown into the water, there are 
seemingly hordes of dogfish, These could be taken with the utmost 
ease and would make an abundant source of material on which to 
operate a fertilizer plant. It must be borne in mind, however, that 
when the food supply which now attracts them to the canneries is 
cut off, as it would be if a by-products plant were instituted in con- 
nection with the cannery, they would cease to congregate there in 
such numbers. Also, if attacked by any of the present methods of 
