Please use this identifier to cite or link to this item:
Appears in Collections:Aquaculture Journal Articles
Peer Review Status: Refereed
Title: Effects of light regime on diurnal plasma melatonin levels and vertical distribution in farmed Atlantic cod (Gadus morhua L.)
Author(s): Skulstad, Ole Fredrik
Taylor, John
Davie, Andrew
Migaud, Herve
Kristiansen, Tore S
Mayer, Ian
Taranger, Geir Lasse
Olsen, Rolf E
Karlsen, Orjan
Contact Email:
Keywords: Light intensity
Light perception
Light position
Issue Date: Nov-2013
Citation: Skulstad OF, Taylor J, Davie A, Migaud H, Kristiansen TS, Mayer I, Taranger GL, Olsen RE & Karlsen O (2013) Effects of light regime on diurnal plasma melatonin levels and vertical distribution in farmed Atlantic cod (Gadus morhua L.), Aquaculture, 414-415, pp. 280-287.
Abstract: Two studies were performed to study the effect of different light intensities on melatonin secretory profiles in Atlantic cod (Gadus morhua L.). In an indoor tank study, plasma melatonin profiles were measured over a 24-hour cycle in juvenile Atlantic cod reared under a 12 h light:12 h dark photoperiod, having either a high or low daytime light intensity (15.5 or 0.16 μE·cm- 2·s- 1). In a second study, plasma melatonin levels were measured in Atlantic cod kept in traps at three depths (4, 9 and 14 m) in a large sea cage following exposure to the following five experimental light regimes: (1) natural light (NL), (2) NL + artificial constant light (LL) at 2, 7 and 12 m depth, (3) NL + LL at 2 or 12 m, (4) NL + LL at 2 m and (5) NL + LL at 2 m together with additional surface shading. The vertical distribution of free swimming Atlantic cod in the same sea cage was monitored using hydroacoustics. In the tank experiment, diurnal plasma melatonin profiles were similar under low and high light intensity, remaining low during the light period, then increasing rapidly within 15-30 min of lights off, before peaking around midnight. In the sea cage experiment, fish under NL showed a similar diurnal rhythm in plasma melatonin levels, with high melatonin levels during the dark period, although at sunrise melatonin levels started to fall earlier in fish kept at 4 m depth compared to fish kept at 9 and 14 m. Overall, melatonin profiles were most effectively reduced, in terms of relative (day/night) plasma levels, in those fish sampled at the deepest depth (14 m). Relative plasma melatonin levels were correlated to the distance from the artificial light source and the intensity of the ambient light. Dispersed light (lamps at 2, 7 and 12 m) was the most effective light regime for inhibiting the nocturnal rise in plasma melatonin ratios in fish sampled at all three depths. Finally, exposure to the different light regimes did not influence the vertical distribution of Atlantic cod within the sea cage, which consistently remained close to the bottom of the cage.
DOI Link:
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.

Files in This Item:
File Description SizeFormat 
1-s2.0-S0044848613004055-main.pdf3.45 MBAdobe PDFUnder Permanent Embargo    Request a copy

Note: If any of the files in this item are currently embargoed, you can request a copy directly from the author by clicking the padlock icon above. However, this facility is dependent on the depositor still being contactable at their original email address.

This item is protected by original copyright

Items in the Repository are protected by copyright, with all rights reserved, unless otherwise indicated.

If you believe that any material held in STORRE infringes copyright, please contact providing details and we will remove the Work from public display in STORRE and investigate your claim.