PROGRESS IN BIOLOGICAL INQUIRIES, 1939 4l 
In the 1939 experiments a smaller return was made locally from 
the tagging at East Anchor Cove than was made from the tagging 
close to False Pass, indicating that in general the fish were moving 
away from the Pass. The relatively high percentage of marked 
fish recovered south of Unimak Island, and the abundance of migrat- 
ing red salmon along this entire shore, shows that a fairly large 
number of fish travel by this route after leaving Ikatan Bay. These 
fish would enter Bristol Bay via Unimak Pass or other passes to the 
westward. 
Local fishermen who have tried to catch fish in False Pass report 
that there are no red salmon to be found in the northern half of 
the Pass, and that while red salmon enter False Pass they do not go 
through but return to Ikatan Bay. While it is possible that some red 
salmon do go through False Pass, it is certain that a fairly large num- 
ber proceed from Ikatan Bay to Bristol Bay via Unimak Pass and 
other passes to the westward. 
A study of the migration routes of the Bristol Bay red salmon 
populations was also made in the off-shore waters, both north and 
south of the Alaska Peninsula, by operating various types of- fishing 
gear at varying distances from shore. The data obtained from this 
research are of considerable value in determining the areas traversed 
by the salmon on their return to their home streams, and also the 
types of organisms taken by them for food. 
The U. S. Coast Guard again cooperated with the Bureau of 
Fisheries by furnishing the cutter Redwing for the purpose of con- 
ducting the oceanographic survey of Bristol Bay and contiguous 
waters. New anchor gear and a sonic depthfinder were installed on 
the Redwing early in the spring to facilitate the carrying on of the 
oceanographic studies, which require numerous stops for samples 
and for frequent and accurate soundings. 
Samples were obtained at all stations in Bristol Bay proper prior 
to the time of the fish run, during the run, and again after the 
run has passed by. In addition, some samples were taken between 
Unalaska Island and the Pribilof Islands. Temperature data and 
plankton samples were collected, and chemical analyses were made 
of the water taken at various depths from each station, to determine 
the oxygen, chloride, silicate, phosphate, and nitrite content of the 
water. The purpose of the oceanographic surveys is to determine 
the environmental conditions in the areas in which the fish spend 
a part or all of their sojourn in the ocean. 
KARLUK RIVER RED SALMON 
Further studies to determine the extent and causes of the fluctua- 
tions in the size of the red-salmon runs to the Karluk River, Alaska, 
were conducted in 1939 by Allan C. DeLacy and William M. Morton. 
The period of field work extended from May 1 to October 5, and the 
tabulation and analysis of data occupied the balance of the year. 
The runs of red salmon to the Karluk River have shown great 
fluctuations in abundance during the 19-year period in which they 
have been under observation by the Bureau of Fisheries. From 1887 
to 1908 the commercial catch of red salmon in the Karluk area 
averaged 2,500,000 fish per year. Following this period, the com- 
mercial catch has exceeded 2,000,000 fish in only 1916, 1917, and 
