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Environmental influences on melatonin secretion in Atlantic cod (Gadus morhua) and their relevance to commercial culture
journal contribution
posted on 2023-05-16, 16:31 authored by Porter, MJR, Stefansson, SO, Nyhammer, G, Karlson, O, Norberg, B, Bromage, NRThis study investigated the effects of photoperiod and temperature on plasma melatonin secretion in Atlantic cod (Gadus morhua L.). Initial work confirmed the presence of a diel profile of melatonin synthesis, with elevated levels during the dark phase. Unusually for fish, the peak in plasma melatonin occurred towards the end of the dark phase, which is indicative of a type 'A' melatonin profile. When exposed to 60 hours of continuous darkness a clear endogenous rhythm of melatonin synthesis was observed, which continued for 4 cycles with a periodicity which, approximated to 24 h. When acclimated to varying temperatures (4, 8, 12 or 16 °C) no variation in melatonin production was seen, however, body size appeared to be an important influence, with the smallest fish exhibiting significantly higher levels of dark phase melatonin. Finally, the application of additional night-time illumination to cod maintained in sea cages i.e. without blackout, did not significantly reduce dark phase plasma melatonin, suggesting that cod are less sensitive to photoperiod manipulation in cages than salmonids.
History
Publication title
Fish Physiology and BiochemistryVolume
23Pagination
191-200ISSN
0920-1742Department/School
Institute for Marine and Antarctic StudiesPublisher
Springer-Verlag DordrechtPlace of publication
NetherlandsRepository Status
- Restricted