80 U. S. BUREAU OF FISHERIES 
CALIFORNIA TROUT AND SALMON INVESTIGATIONS 
The management problems now being investigated, under the direc- 
tion of Dr. P. R. Needham, include three major phases: (1) Coopera- 
tive stream and lake surveys and catch record work with the United 
States Forest Service in California and Oregon; (2), operation of 
the Convict Creek experimental stream, near Bishop, Calif.; and (3), 
studies of salmon that will be prevented from migrating to their 
spawning grounds on the upper Sacramento River because of the 
Shasta Dam. 
Cooperation with the Forest Service was curtailed, owing to lack 
of funds. However, stream and lake surveys were carried on in the 
Mount Hood and Fremont National Forests in Oregon, and the 
Whitman National Forest in Washington. Complete catch records 
were secured for a third angling season on Squaw Creek, in the 
Shasta National Forest, California. A report covering 3 seasons’ 
work on this stream is now in preparation. 
Mewican. trout.—A second trip was made to Lower California to 
secure Salmo nelsoni to replace the first lot lost during the flood in 
March 1938. These trout, inhabiting the warm and isolated Rio 
Santo Domingo, were secured to try and develop a stock which will 
be tolerant of warm water and nonmigratory. The trip was highly 
successful, and 325 fingerlings between 2 and 4 inches long were 
transported by truck to the experimental stream near Bishop, with- 
out the loss of a single fish. Later they were transferred to the 
Clarkamas Hatchery, near Portland, Oreg. 
Convict Creek experimental stream—The_ season’s work was 
begun on April 25. Construction of the large cabin begun in 1938 
was completed, and a diversion ditch was excavated around the ex- 
perimental area to by-pass excess water during spring floods. 
Studies were again concerned with the problem of the survival 
of trout after planting. Winter conditions in this region permit only 
seasonal operation. In the season of 1937 the planting experiments 
were operated for a period of approximately 75 days; in 1938 this 
was extended to 90 days; and, in 1939, to 107 days. 
A new experimental section over 800 teet im length was made 
available by the construction of a concrete flume screened at the 
upper and lower ends. <All wild fish were removed from the section 
which was then stocked with 1.4-in. Loch Leven trout. The survival 
after 107 days was 87 percent, and the average length 2.64 in. In 
general, survival rates in 1939 were less than in 19388, which is sur- 
prising in view of the fact that the number of wild fish competing 
with the planted fish was greater in 1938. Survival records for 3 
years have now been accumulated, but owing to limited personnel 
a thorough analysis of the data has been impossible. 
A population study was made in two series of pools in Convict 
Creek—one below the experimental area in open waters, and one 
within the area where no fishing is permitted. It was found that 
the section open to angling contained 3.8 trout, 6 in. long, per 
pool, while in the closed section there were 14.5 trout per pool. 
While pools in the section open to angling contained fewer large 
trout, they contained larger numbers of fish of the younger age- 
groups than pools in the closed section. It is interesting that such 
