Critical daylength and temperature level for photoperiodism in gonadal maturation of goldfish.
When yearling goldfish were exposed to 12, 13, 14, 15 or 16 L at 24 degrees C from 27 October-27 December, females were suppressed at 12 or 13 L but matured to spawn at other daylengths. The critical daylength was thus located at 13-14 L. Males were not suppressed at any daylength, and spermiated to pass quickly into the post-spawning stage, commencing the next maturation cycle after completion of the regressive stage. When exposed to 12 or 16 L at 18 or 21 degrees C from 5 December-5 March, a few females matured and spawned at 21 degrees C/12 L, while most females did so on other regimes. The temperature level, below which the photoperiodic response became indistinct, was between 18 degrees and 21 degrees C. Most males continued spermatogenesis at 18 degrees C/16 L, but they spermiated and passed into the post-spawning stage quickly on other regimes.
Razani
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H
Department of Fisheries, Faculty of Agriculture, University of Tokyo, Japan.
Hanyu
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Aida
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K
D000818:Animals; D003530:Cyprinidae / Q000502:physiology*; D005260:Female; D006054:Goldfish / Q000502:physiology*; D008027:Light; D008297:Male; D010050:Ovarian Function Tests; D012741:Sexual Maturation; D013696:Temperature; D013737:Testis / Q000166:cytology