Northwest Fisheries Science Center

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Document Type: Chapter or Section
Center: NWFSC
Document ID: 8911
Type of Book: Technical
Section or Chapter Title: Activity cycles of juvenile salmon
Book Title: Fish-Passage Research Program review of progress 1964, Volume V
Author: Theodore H. Blahm
Editor: Gerald B. Collins, Carl H. Elling (Eds.)
Publication Year: 1964
Publisher: Report of the Accelerated Fish-Passage Research Program to the U.S. Bureau of Commercial Fisheries. Seattle, Washington

This paper reports a recently developed method of activity detection which provides a continuous graphic record for periods of one week or longer, and requires a minimum amount of attention by the operator.  To test this system, a series of observations using three species of salmon fingerling—sockeye Oncorhynchus nerka, silver O. kisutch, and chinook O. tshawytscha—was undertaken at the Behavior Laboratory, Fish-Passage Research Program, Seattle, Washington.

Of 27 sockeye tested, 24 or 90% demonstrated a period of evening activity.  Observation periods ranged 24-192 h (1-8 d).  Of the juvenile sockeye tested for longer than one 24-h period, 70% repeated their period of activity one or more times.  The replication occurred even though the observations were made under darkened conditions.

Twenty-four silver salmon were tested, and 78% of these fish demonstrated approximately the same pattern as the sockeye, but greater individual variation.  The 18 chinook tested exhibited activity of a sporadic nature, with active periods more concentrated during late evening and early morning hours.

Data collected to date indicate that there are activity cycles within the behavioral patterns of juvenile salmon.  The information also indicates, to some degree, that there are species differences.