Photoperiod and its effect on incidence of sexual maturity in pink salmon ( Oncorhynchus gorbuscha )

• Published in: Canadian Journal of Zoology
• Main Authors: Beacham, Terry D., Murray, Clyde B.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1990
• Subjects: Animal Science and Zoology; Ecology, Evolution, Behavior and Systematics; Oncorhynchus gorbuscha; Pink salmon
• Online Access: http://dx.doi.org/10.1139/z90-180; http://www.nrcresearchpress.com/doi/pdf/10.1139/z90-180

Pink salmon (Oncorhynchus gorbuscha) were reared for 15 months after fry emergence under three photoperiod regimes. About 50% of males matured in a photoperiod that had two periods of declining day length within the 15-month study period. No males matured in photoperiods having only one period of declining day length, and no females matured in any photoperiod. The rate of change of day length is likely of greater importance than the amplitude of change in inducing sexual maturation in males.