PROGRESS IN BIOLOGICAL INQUIRIES, 1938 33 
Payette Lake, at the headwaters of the North Fork, is reported to 
have supported a run of blueback salmon. Dams without adequate 
fish protection are responsible to a great extent for the extinction of 
the salmon runs in this river. A dam constructed at Horseshoe 
Bend 30 years ago probably destroyed the blueback run which had 
entered Payette Lake, and limited the migration of chinooks and 
steelheads to the part of the river below this obstruction. In 1925 
the Black Canyon Dam was constructed by the United States Recla- 
mation Service. This dam is a complete barrier to all migratory 
fish, since no fish protection was provided. It is reported that there 
have been fewer salmon observed below the dam each year. The 
stream survey revealed that the amount of favorable spawning area 
in the Payette River system is great enough to provide facilities for 
a large run of fish, if access to the spawning grounds were provided. 
Stream surveys were carried on in 258 miles of the Clearwater 
River, including the main river from the mouth to Kamiah Creek, 
Potlatch Creek, North Fork to Kelly Creek, Middle Fork, Sellway 
River to Meadow Creek, and the Lochsa to Fire Creek. Some 500 
miles of this large river system remain to be examined. 
Stream surveys were also started on the Klickitat River but only 
38 miles had been surveyed when winter weather conditions forced 
the termination of the survey for the season. 
A total of 1,177 miles of stream was surveyed during the season. 
Information obtained from these surveys was made available to 
various interested agencies. 
Salmon redds and spawning habits —An investigation was under- 
taken to study the spawning habits of spring and fall chinook, silver, 
and chum salmon as an aid in interpreting the results of the stream 
survey. The information gained as a result of this investigation is 
as follows: (1) The space required for each pair of spawning fish, 
(2) type of gravel selected, (3) depth of water preferred, and (4) 
temperature prevailing at the time of spawning. In addition, case 
histories of individual redds were recorded, including data on the 
longitudinal and horizontal measurements of the redds, the time of 
the male intervention, the deposition of the ova, and superimposition 
and succession of the redds. These studies were conducted in the 
Kalama, Ohanopecosh, Toutle, Grays, German, Abernathy, and 
Alochaman Rivers. 
During the period of investigation information was obtained on 
486 salmon redds in these rivers. The results of this study are now 
being analyzed and a report for publication will be submitted in the 
near future. c 
Tagging. —A series of 25 tagging experiments were conducted in 
the Columbia River on spring and fall chinooks which pass through 
the fishery from May 1 to the latter part of August and early Sep- 
tember. ‘The purpose of these experiments is to obtain data on (1) 
the rate of migration of the salmon upstream, (2) their distribution 
in the river system, (3) their appearance at hatcheries, and (4) some 
estimate of fishing mortality. These experiments will contribute 
invaluable information as a basis for regulation of the fishery and 
for stocking policies. oe 
The experiments were carried out at three localities on the river, 
Sand Island, Woody Island, and in the vicinity of Oak Point. These 
