This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Randall, C. F. Articles by Symes, J. Search for Related Content PubMed PubMed Citation Articles by Randall, C. F. Articles by Symes, J.

Photoperiod-induced phase-shifts of the endogenous clock controlling reproduction in the rainbow trout: a circannual phase–response curve

Different groups of winter-spawning female rainbow trout that had been maintained under seasonally changing daylength and temperature were exposed to 2 months of continuous light at different times of the year. The same photoperiod produced advances in the time of spawning of up to 232 days and delays of up to 80 days, depending upon the timing of exposure in relation to the phase of the reproductive cycle. The proportion of fish spawning in each group varied from 18% to 100%, again dependent on the timing of exposure to continuous light. The photoperiod-induced changes in spawning time can be interpreted as phase-dependent phase-shifts of an endogenous circannual clock controlling maturation. It is proposed that long days, occurring earlier or later than they would under a natural photoperiod, were perceived as indications that the clock was running slow or fast, thus initiating corrective forward adjustments (advance phase-shifts) or backward adjustments (delay phase-shifts), respectively. Collectively, these responses can be described in the form of a circannual phase–response curve.

This article has been cited by other articles:

				K. S. Last and P. J. W. Olive Interaction Between Photoperiod and an Endogenous Seasonal Factor in Influencing the Diel Locomotor Activity of the Benthic Polychaete Nereis virens Sars Biol. Bull., April 1, 2004; 206(2): 103 - 112. [Abstract] [Full Text]

				G. K. Barrell, L. A. Thrun, M. E. Brown, C. Viguié, and F. J. Karsch Importance of Photoperiodic Signal Quality to Entrainment of the Circannual Reproductive Rhythm of the Ewe Biol Reprod, September 1, 2000; 63(3): 769 - 774. [Abstract] [Full Text]

				S. D. McCormick, S. Moriyama, and B. T. Bjornsson Low temperature limits photoperiod control of smolting in Atlantic salmon through endocrine mechanisms Am J Physiol Regulatory Integrative Comp Physiol, May 1, 2000; 278(5): R1352 - R1361. [Abstract] [Full Text] [PDF]