A measured delay in the migration of adult chinook salmon at Bonneville Dam on the Columbia River
By: Robert W. Schoning and Donald R. Johnson.
Contributors: Johnson, Donald R.; Oregon. Fish Commission.
Series: Contribution / Oregon Fish Commission -- no. 23.; Contribution (Oregon. Fish Commission) -- no. 23.
Publisher: Fish Commission of Oregon
Published: 1956
Place of publication: Portland
Language: eng
Number of pages: 16
Subjects: Chinook salmon -- Migration -- Columbia River.; Chinook salmon -- Effect of dams on -- Columbia River.; Chinook salmon -- Bonneville Dam (Or. and Wash.)
Description: A study was undertaken in the fall of 1948 by the Oregon Fish Commission to determine the possible presence and importance of a delay in the migration of adult chinook salmon (Oncorhynchus tshawytscha) at Bonneville Dam on the Columbia River. Approximately 650 chinook were captured, tagged, and released at the Oneonta trap 6.7 miles below Bonneville Dam and 200 were handled similarly at the dam and released above. The tag returns from Celilo Falls, the main commercial fishing area, 60 miles above Bonneville, were compared by location of tagging with regard to date of tagging and the number of days en route. The linear correlation between tagging date and days out was significant for the 39 recoveries tagged at Bonneville but not for the 35 from Oneonta. The later in the season the fish were tagged at Bonneville the more rapidly they migrated to Celilo Falls. With no adjustment for the difference in distance between the two tagging locations, the fish from Oneonta took a significant 3.4 days longer to make the trip to Celilo than the Bonneville tagged fish. When correcting for the distance difference, the delay was reduced to 3.0 or 2.6 days, either of which was still significant. Although the number of recoveries is small, all of those used are believed to be reliable and sufficient for statistical analysis. The study represents only one year's work and investigations of another year may refute or substantiate these findings.
Notes: "May 1956."

Bibliography: p. 14.

Also issued online.
Table of contents: value: Abstract; value: Introduction; value: Tagging and recovery; value: Effect of dam on migration rate; value: Discussion; value: Acknowledgments; value: Literature cited.