PROGRESS IN BIOLOGICAL INQUIRIES, 1938 35 
found in the different streams of the Puget Sound region, the deter- 
mination of the causes for the decline in its abundance, and the 
development of methods for rebuilding the runs was continued during 
the past year by George B. Kelez. 
The series of three marking experiments undertaken during the 
fall and winter of 19387 at the Quileene (Wash.) station of the Divi- 
sion of Fish Culture * was completed, during the month of May, with 
the marking of 17,094 coho fingerlings of the 1936 brood. These fish 
had been held for the purpose of releasing them at the approximate 
time of normal seaward migration. At the time of this last release, 
marked individuals from the lots released in September and Decem- 
ber 1937 could still be observed in the Quilcene River in the vicinity 
of the hatchery. It is expected that comparative returns from these 
experiments will provide further information both on the success of 
various periods of hatchery rearing and on the relation of the addi- 
tional costs of prolonged rearing to the increased survival rate of the 
fingerlings hberated. 
No further recoveries of marked fish from the 1935 experiment on 
Voights Creek, tributary to the Puyallup River, were made during 
the late winter run, and none were taken from the Green River.’ 
Several tags from the 1937 Samish River experiment were returned 
to the laboratory during the spring and summer. This experiment 
was undertaken to test the practicability of marking fingerlings by 
the use of an internal celluloid tag in combination with the excision 
of the dorsal fin, as an alternative to the usual method of marking in 
which two or more fins are removed. If this method is successful, it 
will eliminate the present limitation on the number of possible experi- 
ments which the number of available fin combinations imposes. 
Collections of scale samples and biological data from mature cohos 
taken in the commercial fishery were made during the season. Sam- 
ples aggregating approximately 4,500 fish were taken during the 
summer fishery at Anacortes, Wash., and samples of more than 2,000 
fish were taken during the fall fishery at Seattle. Supplementary 
samples and catch data were collected during the season from the 
sport fishery carried on in the vicinity of Seattle. Collections of coho 
fingerlings were also taken during the season from the sport fishery 
carried on in the vicinity of Seattle and the major streams tributary 
to Puget Sound. ; 
During the spawning migration regular collections of scale samples 
were taken and estimates of population size were made on all streams 
tributary to Puget Sound on the eastern shore. It is believed that 
variations in early life history, as shown by the scale nucleii, will 
differ sufficiently between the colder northern streams and the warmer 
southern ones to afford a means of separating these populations on the 
basis of scale characteristics. Through a comparison of samples of 
scales taken from the commercial fishery with those from the two 
spawning areas, the relative contribution of these districts to the 
fishery may be determined. 
Observations on the spawning grounds during the fall and early 
winter indicate that, although the total escapement of cohos was not 
large this year, spawners were well distributed in all the streams of 
the region. 
2 See “Progress in Biological Inquiries, 1937.” 
