PROGRESS IN BIOLOGICAL INQUIRIES, 1926 635 
to make a study of the causes of fluctuations in abundance. We can now under- 
take not merely a study of the fluctuations in abundance, determining their 
existence, extent, and nature, but an investigation of some of the causes of 
these fluctuations, and a considerable part of our present program is directed 
along that line, although not exclusively. 
A couple of years ago the United States and Canada and the fish commissions 
of the west coast organized a group known as the International Pacific Salmon 
Investigation Federation, for the purpose of coordinating the work of the 
salmon investigations. The State of California, the Canadian authorities, and 
the Bureau of Fisheries were each working on salmon investigations. This 
federation was for the purpose of coordinating these various efforts. 
At the last meeting of this federation, a program was presented and was 
accepted by the executive committee of the federation which will give you, 
very briefly, about as good an outline as I can present of the work that is 
being undertaken and projected. With your permission, I shall simp y read this 
report. 
The subcommittee wishes first to express its belief that the primary purpose of any 
program of research should be to produce the essential knowledge needed for the proper 
and scientific administration of the salmon fisheries. Our desire is to conserve effec- 
tively the great salmon resources of the North Pacific, and our conception of such 
conservation involves the utilization of the resources to the fullest extent compatible 
with their perpetuation. We would like to be able to say definitely how many salmon 
it would be possible to take from a given region and still leave sufficient for spawning 
purposes so that the supply will continue year after year at a high level. It has been 
brought out repeatedly at both of the previous meetings of this committee, that the 
central idea about which we should build our program is the production of the maximum 
yield obtainable from this fishery; and by the maximum yield is meant the greatest 
production of fish that may be taken for commercial purposes without affecting the future 
supply. To provide adequately for this we must know: (1) What natural fluctuations 
in the abundance of salmon occur; (2) the causes of these fluctuations, particularly 
the immediate causes, though the ultimate causes should finally be known; (3) the 
intensity with which the commercial fishery is conducted and its effect on the future 
supply; and (4) the relative value of various measures that may be used to prevent 
depletion and to build up runs already depleted. With these fundamental requirements in 
mind, the following program is presented: 
COLLECTION OF ADEQUATE AND UNIFORM STATISTICS 
These are of fundamental importance and should include not only data that will 
show the trend of the yield of each stream or fishing area, but the trend of the fishing 
effort. Reliable statistics are indispensable to. a determination of the fluctuations in 
abundance, and without these all our other efforts can be of little value. It is recom- 
mended that a separate subcommittee be appointed to consider the reliability of the 
present statistics and to suggest desired changes, either in the content, manner of 
collection, or manner of presentation. 
TAGGING EXPERIMENTS 
The tagging experiments conducted in the past have been productive of a great deal 
of valuable information relative to the oceanic migrations of the salmon and bearing 
on the relationship existing between the salmon found in various regions. This should 
be continued until we understand, with considerable thoroughness, these features of the 
distribution of the salmon along the coast. Such data are essential to the proper inter- 
pretation of the statistics, and only in this way can be know the true yield of a given 
Stream or region. (The importance of such data is well known in the results obtained 
from the tagging along the Alaska Peninsula, through which it was determined that 
the fish caught in the Ikatan—Shumagin Island district were largely from the productive 
Streams of Bristol Bay.) 
SCALE ANALYSES OF THE ADULT RUNS 
This is essential to any understanding of the causes, either immediate or ultimate, 
responsible for the fluctuations in abundance, and likewise will provide the necessary 
data on which may be based prophecies of future runs. By this means only can we 
determine the productivity of each brood year, the relative effects of heavy and light 
seedings of the spawning beds, the effect of various methods of artificial propagation, 
and of modifications in the intensity of fishing, etc. Such studies are being carried out 
already On a number of the more important salmon streams, and it is important that 
they be extended to others. They must be continued indefinitely as long as any salmon 
research is being conducted. 
STUDY OF THE ADULT RETURNS FROM KNOWN ESCAPEMENTS TO THE SPAWNING 
GROUNDS 
This line of investigation must be carried out on specially selected streams where the 
production can be accurately determined. The number of fish taken each year in the 
commercial fishery must be known, as well as the number of fish ascending to the spawn- 
ing grounds. In this way the effect of variations in the spawning escapement may be 
worked out, as well as the natural fluctuations in production, from a given escapement. 
