Estimation of Mid-Columbia Summer Chinook Salmon Escapement and Age Composition Using PIT Tags in 2008
In 2008, a total of 644 spring, 904 summer, and 1280 fall Chinook salmon (Oncorhynchus tshawytscha) were tagged with 12.5 mm PIT tags at Bonneville Dam between April 15 and October 14. An additional 312 spring and 235 summer Chinook salmon were tagged with 8.5 mm PIT tags; however, poor detection at some dams (principally Priest Rapids, Rock Island, and Rocky Reach Dams where 64.3%, 41.9%, and 12.6% respectively were not detected) resulted in these data being ignored in calculating results. After adding previously tagged fish, and subtracting fish that likely shed PIT tags, a total of 663 spring Chinook, 913 summer Chinook, and 1285 fall Chinook were tracked upstream. Data collected from the upstream migration of these fish were used to (1) compare detection rates of different PIT tag models, (2) evaluate migration speed and timing, and (3) estimate abundance of different species.
Fryer, J.K. 2009. Estimation of Mid-Columbia summer Chinook salmon Escapement and Age Composition using PIT tags in 2008. Columbia River Inter-Tribal Fish Commission Technical Report 09-04, Portland, Oregon. 52p.