Migratory Behavior and Physiological Development as Potential Determinants of Life History Diversity in Fall Chinook Salmon in the Clearwater River

Journal Article · Fri Mar 09 00:00:00 EST 2018 · Transactions of the American Fisheries Society

DOI:https://doi.org/10.1002/tafs.10035· OSTI ID:1581973

Tiffan, Kenneth F. ^[1]; Kock, Tobias J. ^[2]; Connor, William P. ^[2]; Richmond, Marshall C.  ^[3]; Perkins, William A.  ^[3]

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1. United States Geological Survey
2. US GEOLOGICAL SURVEY
3. BATTELLE (PACIFIC NW LAB)

We studied the influence of behavior, water velocity, and physiological development on the downstream movement of subyearling fall Chinook Salmon Oncorhynchus tshawytscha in free-flowing and impounded reaches of the Clearwater and Snake rivers as potential mechanisms that might explain life history diversity in this stock. Movement rates and the percentage of radio-tagged fish that moved faster than the average current velocity were highest in the free-flowing Clearwater River compared to impounded reaches. This provided support for our hypothesis that water velocity is a primary determinant of downstream movement regardless of a fish’s physiological development. In contrast, movement rates slowed and detections became fewer in impounded reaches where velocities were much lower. The percentage of fish that moved faster than the average current velocity continued to decline and reached zero in the lower-most reach of Lower Granite Reservoir suggesting that behavioral disposition to move downstream was low. These findings contrast those of a similar, previous study of Snake River subyearlings in spite of hydrodynamic conditions being similar. Physiological differences between Snake and Clearwater river migrants shed light on this disparity. Subyearlings from the Clearwater River were parr-like in their development and never showed an increase in gill Na+/K+-ATPase activity as did smolts from the Snake River. The later emergence timing and cooler rearing temperatures in the Clearwater River may suppress normal physiological development that causes many fish to delay downstream movement and adopt a yearling life history strategy.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1581973
• Report Number(s): PNNL-SA-130393
• Journal Information: Transactions of the American Fisheries Society, Vol. 147, Issue 2
• Country of Publication: United States
• Language: English