Migratory behavior and physiological development as potential determinants of life history diversity in fall Chinook Salmon in the Clearwater River

Transactions of the American Fisheries Society
By: , and 

Links

Abstract

We studied the influence of behavior, water velocity, and physiological development on the downstream movement of subyearling fall‐run Chinook Salmon Oncorhynchus tshawytscha in both 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 higher in the free‐flowing Clearwater River than in impounded reaches. This supports the notion 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 water velocities were much lower. The percentage of fish that moved faster than the average current velocity continued to decline and reached zero in the lowermost reach of Lower Granite Reservoir, suggesting that the behavioral disposition to move downstream was low. These findings contrast with those of a similar, previous study of Snake River subyearlings despite similarity in hydrodynamic conditions between the two studies. 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 the increase in gill Na+/K+‐ATPase activity displayed by smolts from the Snake River. Results from this study provide evidence that behavioral and life history differences between Snake and Clearwater River subyearlings may have a physiological basis that is modified by environmental conditions.

Study Area

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Migratory behavior and physiological development as potential determinants of life history diversity in fall Chinook Salmon in the Clearwater River
Series title Transactions of the American Fisheries Society
DOI 10.1002/tafs.10035
Volume 147
Issue 2
Year Published 2018
Language English
Publisher Wiley
Contributing office(s) Western Fisheries Research Center
Description 14 p.
First page 400
Last page 413
Country nited States
State Idaho, Washington
Other Geospatial Clearwater River, Snake River