36 U. 8. BUREAU OF FISHERIES 
BRISTOL BAY SALMON FISHERIES 
The Bristol Bay region of Alaska is the greatest red-salmon pro- 
ducing area in the world, providing, as it does, more than 60,000,000 
pounds of first quality canned salmon a year. Sporadic studies of the 
salmon in this area have been carried on since 1922, and information 
has been obtained on the age and migration habits of some of the 
populations inhabiting the five major watersheds in this region. 
The recent development of extensive offshore fishing has been con- 
sidered a possible source of serious injury to this salmon fishery. 
The fact that there is little available knowledge of the life history 
of salmon in this area, and of the factors affecting the survival of the 
populations as a whole, made it imperative to inaugurate a thorough 
biological study of the fish of this region, their migration routes and 
the factors affecting their survival. An appropriation was made 
available on July 1 for the purpose of carrying on the first year’s 
study of a 5-year program of investigation. The problems entailed 
in such an investigation are manifold and must necessarily include 
studies of a multitude of factors, biological, physical, and chemical, 
affecting the species from the time the eggs are deposited in the 
gravels in the upper reaches of the watersheds until the progeny 
from one year’s spawning have completed their life cycle and have 
deposited the fertilized eggs from which another brood will result. 
The investigation separates itself into two distinct though related 
divisions, the fresh-water and the marine, which are being carried on 
by George B. Kelez and J. T. Barnaby, respectively. 
Fresh-water studies —The principal activities of this phase of the 
investigation consist of the determination of the physical and biolog- 
ical characteristics of the fresh-water areas of the Bristol Bay 
region, the evaluation of the annual spawning populations, age 
analyses of the runs in the various rivers, and the measurement of 
factors influencing the mortality of the eggs and young fish in fresh 
water. 
During the past season reconnaissance surveys of the five main 
river systems of the region were made, in which the general topo- 
graphical features of the watersheds, the number and size of the 
headwater lakes and tributary streams, and the extent of the spawn- 
ing areas were noted. From these observations thorough surveys of 
important spawning grounds have been planned and areas selected 
for carrying on marking experiments, migrant collections, and 
similar studies. 
A number of small lakes, typical of the particular watersheds in 
which they lie, were inspected, and several suitable ones chosen for 
studies of the biological characteristics of the environment in which 
the young fish grow and develop. Here, also, the effect of varying 
climatic conditions on the survival of the stocks may be determined. 
Methods of handling the commercial catch at the canneries were 
observed and plans were made for a complete annual program of 
random sampling of the catch in which scale samples will be taken 
for age analysis. Data on size, weight, and sex ratio will be obtained 
for population studies. These collections will be supplemented by 
similar sampling on the spawning grounds of each river system. 
From this material the age-group composition of each year’s run, the 
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