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Quantifying the behavioral response of spawning chum salmon to elevated discharges from Bonneville Dam, Columbia River, USA

River Research and Applications

By:
, ,
DOI: 10.1002/rra.1248

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Abstract

Chum salmon Oncorhynchus keta that spawn in main-stem habitats below Bonneville Dam on the Columbia River, USA, are periodically subjected to elevated discharges that may alter spawning behaviour. We investigated behavioural responses of spawning chum salmon to increased water velocities associated with experimental increases in tailwater elevation using acoustic telemetry and a dual-frequency identification sonar. Chum salmon primarily remained near their redds at base tailwater elevations (3.5 m above mean sea level), but displayed different movement and behavioural responses as elevations were increased to either 4.1 or 4.7m for 8-h periods. When velocities remained suitable (<0.8m s-1) during elevated-tailwater tests, female chum salmon remained near their redds but exhibited reduced digging activity as water velocities increased. However, when velocities exceeded 0.8m s-1, the females that remained on their redds exhibited increased swimming activity and digging virtually ceased. Female and male chum salmon that left their redds when velocities became unsuitable moved mean distances ranging from 32 to 58 m to occupy suitable velocities, but returned to their redds after tailwaters returned to base levels. Spawning events (i.e. egg deposition) were observed for five of nine pairs of chum salmon following tests indicating any disruptions to normal behaviour caused by elevated tailwaters were likely temporary. We believe a chum salmon's decision to either remain on, or leave, its redd during periods of unsuitably high water velocities reflects time invested in the redd and the associated energetic costs it is willing to incur. ?? 2009 John Wiley & Sons, Ltd.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Quantifying the behavioral response of spawning chum salmon to elevated discharges from Bonneville Dam, Columbia River, USA
Series title:
River Research and Applications
DOI:
10.1002/rra.1248
Volume
26
Issue:
2
Year Published:
2010
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
87
Last page:
101
Number of Pages:
15