"December, 1964"

Job no. 1 Ortmann, D.W. Tests to evaluate methods of estimating anadromous fish sport harvests and escapements

Job no. 2 Bjornn, T.C., D.W. Ortmann and D. Corley Tests to evaluate Chinook spawning ground survey techniques and data

[SN 60] Job no. 3 Bjornn, T.C., D.W. Ortmann, D. Corley and W. Platts The gathering and compilation of relevant data for Idaho salmon and steelhead runs (salmon spawning ground surveys-1963)

Job no. 4 Ortmann, D.W. Determination of the timing and distribution of adult salmon and steelhead runs (south fork of Salmon River)

Job no. 5 Bjornn, T.C. and D. Corley Studies on the production of steelhead trout in Lemhi Big Springs Creek

JOB 1: The chinook salmon and steelhead sport fisheries of the South Fork Salmon River drainage were monitored by checking stations throughout the 1963 fishing seasons. Harvest figures obtained provide a control for evaluation of state-wide postal questionnaire survey harvest estimates. An estimated one-third of the chinook run into the drainage was harvested and both the total run size and the spawning escapement were smaller than average. A larger than normal steelhead harvest was indicated. The run appeared to have been the largest in recent years. The harvest was composed almost entirely of 5- and 6-year-old fish, predominately females. A means of estimating steel-head escapement in the drainage has not been devised. Checking stations enumerated the chinook harvest from the Bear Valley area of the Middle Fork Salmon River drainage. The Middle Fork proper was found to be the mainstay of this fishery, accounting for 85 percent of the harvest from within the checking station area.

JOB 2: Studies were conducted again in 1963 to determine the number and timing of surveys needed to obtain representative data on the sex ratio and length frequency of the chinook salmon spawning escapement. The sex ratio of early and late dying fish has varied from year to year and stream to stream. On some of the test survey streams, at least, a single survey made at the time the largest number of dead fish are available appears to be adequate for obtaining representative data.

JOB 3: Ground and aerial counts of chinook salmon redds in the Salmon and Weiser River drainages were made again in 1963. Most of the areas were counted from the ground in conjunction with the collection of life history data from dead spawners examined on the spawning grounds. There were fewer (7-33 percent) spring-and summer-run chinook salmon counted at the dams in the Columbia and Snake Rivers in 1963 than in 1962. Accordingly, the number of redds counted in the Salmon River drainage in 1963 (7,254) was also down from the count in 1962 (8,616). The number of redds counted in both spring-run and summer-run chinook spawning areas was less than in 1962. The 1963 spring run contained a large percentage of age class 52+ fish, which were predominantly females. In certain areas where large numbers of the 52+ fish spawned, the redd counts in 1963 were similar to those of 1962.

JOB 4: A temporary counting weir in the South Fork of the Salmon River was operated intermittently during the 1963 chinook run to determine the feasibility of the use of such a structure in enumerating chinook runs into the river. After considerable experimentation, satisfactory passage was obtained. It appears that a temporary weir can be used to count the chinook runs into the South Fork of the Salmon River.

JOB 5: This study was initiated to evaluate the production of steelhead trout from plantings of eyed eggs made in an incubation channel adjacent to Lemhi Big Springs Creek. In 1962 and 1963, 92,325 and 613,000 eyed eggs, respectively, were planted in the channel. Survival to the emergent fry stage was 70.6 percent in 1962 (65,185 fry) and 32.0 percent in 1963 (193,545 fry). An increase in the number of age-class I rainbow-steelhead trout was indicated in 1963 over 1962 sampling of the fish population in Lemhi Big Springs Creek with electro-fishing gear. Steelhead trout marked with a fin clip as they were released from the incubation channel in 1962 were among the fish collected in the 1963 samples. Large numbers of juvenile rainbow-steelhead trout leave Lemhi Big Springs Creek after their first summer. Large numbers leave the stream both in the fall and spring with the 1963 fall outmigration larger than the preceding spring migrations. It is likely that the increased outmigration recorded during the fall of 1963 was due, at least in part, to the increased number of steelhead trout fry released into the stream.

F 49-R-25 U.S. Fish & Wildlife Service