Please use this identifier to cite or link to this item: http://hdl.handle.net/1893/19647
Appears in Collections:Aquaculture Journal Articles
Peer Review Status: Refereed
Title: Stocking density affects circadian rhythms of locomotor activity in african catfish, clarias gariepinus
Authors: Vera, LM
Al‐Khamees, Sammi
Migaud, Herve
Contact Email: luisa.veraandujar@stir.ac.uk
Keywords: African catfish
Circadian rhythms
Clara gariepinus
Locomotor activity
Photoperiod
Stocking density
Issue Date: 2011
Publisher: Informa Healthcare
Citation: Vera L, Al‐Khamees S & Migaud H (2011) Stocking density affects circadian rhythms of locomotor activity in african catfish, clarias gariepinus, Chronobiology International, 28 (9), pp. 751-757.
Abstract: The effect of stocking density on the locomotor activity of African catfish C. gariepinus under different light regimes was investigated. C. gariepinus were stocked under different densities (1, 5, or 10 fish/tank), and their locomotor activity recorded under light-dark (LD), constant light (LL), constant darkness (DD), and LD-reversed (DL) regimens. Under the LD cycle, catfish showed a crepuscular activity pattern, irrespective of stocking density, with most of the daily activity concentrated around the light-onset and light-offset times. When fish were subjected to DD, all 4 tanks with medium (5 fish) and high (10 fish) stocking densities showed circadian rhythmicity, with an average period (τ) of 23.3 ± 0.5 and 24.6 ± 0.5 h, respectively. In contrast, only 2 low (1 fish) density tanks showed free-running rhythms. Under LL, activity levels decreased significantly in comparison with levels observed under LD and DD. Moreover, fish of 1, 2, and 3 out of the 4 tanks with low, medium, and high densities, respectively, showed free-running rhythms under these conditions. When the photocycle was reversed (DL), fish of 3, 2, and 4 out of the 4 tanks with low, medium, and high stocking densities, respectively, showed gradual resynchronization to the new phase, and transient cycles of activity were observed. These results suggest that stocking density of fish affected the display of circadian rhythmicity and the intensity of activity levels. Thus, fish kept in higher densities showed more robust rhythmicity and higher levels of daily activity, indicating that social interactions may have an influence on behavioral patterns in the African catfish.Read More: http://informahealthcare.com/doi/abs/10.3109/07420528.2011.606388
Type: Journal Article
URI: http://hdl.handle.net/1893/19647
DOI Link: http://dx.doi.org/10.3109/07420528.2011.606388
Rights: The publisher does not allow this work to be made publicly available in this Repository. Please use the Request a Copy feature at the foot of the Repository record to request a copy directly from the author. You can only request a copy if you wish to use this work for your own research or private study.
Affiliation: Aquaculture
University of Stirling
Aquaculture

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