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The swimming behavior of the copepod Calanus marshallae under various food conditions

ScholarsArchive at Oregon State University

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Title The swimming behavior of the copepod Calanus marshallae under various food conditions
Names Krefft, Kevin P. (creator)
Cowles, Timothy (advisor)
Date Issued 1991-01-24 (iso8601)
Note Graduation date: 1991
Abstract How certain aspects of the swimming behavior of the copepod Calanus
marshallae vary as a function of different food conditions of Thalassiosira weissflogii
was examined. A two video camera recording and controlled food environment
aquaria system were used to record long-term swimming behavior and to determine 3-
dimensional swimming paths during 24-hour and 4-hour experiments. The 24-hour
experiments examined how die! activity level varied with and without food. The 4-
hour experiments examined the following specific behavioral aspects: level of activity,
time allocation between swimming modes, periodicity within modes, and swimming
velocity.
Swimming activity followed a diel pattern when food was available and remained
relatively constant over a 24-hour period when food was not available. Swimming
activity was intermittent, and active intervals consisted primarily of two distinct
swimming modes: rise/sink and looping. A seasonal, or collection date, effect on
swimming activity level and mode existed, and may have been related to the onset of
diapause.
Calanus marshallae modified two aspects of swimming behavior in response to
exposure to food. First, non-feeding individuals did not exhibit looping behavior.
Second, non-feeding individuals had higher rise swimming velocity compared to
feeding individuals. However, none of the examined aspects of swimming behavior
varied significantly among the different food conditions, independent of strong
individual variation. Looping was more periodic and had significantly higher velocity
than rise/sink swimming, yet both modes were effective methods of remaining in a
favorable food patch. The absence of food condition effects suggest that swimming
speed and duration alone may not reflect the food encounter process.
Genre Thesis/Dissertation
Topic Calanoida -- Feeding and feeds
Identifier http://hdl.handle.net/1957/23602

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