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Diel spawning behavior of chum salmon in the Columbia River

Transactions of the American Fisheries Society
By: , , and 
https://doi.org/10.1577/T04-150.1

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Abstract

We conducted a study during 2003 in a side channel of the Columbia River downstream of Bonneville Dam to describe the diel spawning behavior of wild chum salmon Oncorhynchus keta. We collected observational data on 14 pairs of chum salmon using a dual-frequency identification sonar. Spawners of both genders were observed chasing intruders during nighttime and daytime as nests were constructed. Regardless of diel period, females were engaged in digging to both construct nests and cover eggs, and courting males exhibited the prespawning behavior of tail-crossing. We observed a total of 13 spawning events, of which 9 occurred at night and 4 occurred during the day. Once chum salmon begin nest construction, visual cues are apparently not required for courtship, nest defense, and spawning. To enhance successful spawning, flows from Bonneville Dam during the spawning season were reduced during the day but were sometimes increased at night to pass water and meet power demand (i.e., reverse loading), the assumption being that chum salmon are inactive at night. Our findings show that this assumption was violated. Therefore, reverse loading may disrupt the complex prespawning behavior that occurs both during the day and at night, as well as attract spawners to areas that were dewatered during the day.

Publication type Article
Publication Subtype Journal Article
Title Diel spawning behavior of chum salmon in the Columbia River
Series title Transactions of the American Fisheries Society
DOI 10.1577/T04-150.1
Volume 134
Issue 4
Year Published 2005
Language English
Publisher Taylor & Francis
Contributing office(s) Western Fisheries Research Center
Description 9 p.
First page 892
Last page 900
Online Only (Y/N) N
Additional Online Files (Y/N) N
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