• Animal cells and systems
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• 제8권1호
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• pp.33-40
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• 2004

Reproductive cycle and spawning rhythm with lunar cycle of the ascidian, Halocynthia hilgendorfi ritteri were investigated by histological examination. The specimens were sampled in the coastal waters of Yongdam, northwest of Jeju Island, Korea, from November 2001 to January 2003. H. hilgendorfi ritteri is a synchronous hermaphrodite; the gonads are located in the mantle. The reproductive cycle can be grouped into the following successive stages in the ovary: growth (February to June), vitellogenesis (April to September), mature (July to December), spent (November to February), and recovery (December to April). Likewise, in the testis, the stages observed were: growth (October), mature (October to December), spent (November to February), and resting (January to September). Major spawning probably occurs between November and January, when water temperatures decrease. The histological observations of the gonads suggested that this species is a multiple spawner during the spawning period. Spawning occurred between the new moon and full moon, and again between the full moon and new moon, suggesting that the spawning rhythm is influenced by the lunar cycle.

• 수산해양교육연구
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• 제24권6호
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• pp.854-861
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• 2012

To investigate the role of water temperatures and photoperidos as environmental cues regulating reproductive rhythm in banded catfish Pseudobagrus fulvidraco, rearing experiments were conducted using sveral rearing regimes conbined with changes in photoperiods and water temperatures during growing and spawning periods. GSI of $23^{\circ}C$ was significantly higher than $18^{\circ}C$ in female, but 9 light of 18 and $23^{\circ}C$ were no difference in male. In case of estradiol, $18^{\circ}C$ and 15 L was higher than other experintal precinct after 20 days. But, end of the experiment, all of experimental precinct were no difference. Testosteron of female was no difference in $18^{\circ}C$-9 and 15 L after 20 days. Testosteron of male was no difference in $18^{\circ}C$-9 L. In case of 11-KT, control level was $0.39{\pm}0.03$ ng/mL and $18^{\circ}C$-9 L was no significantly difference after 20 days. But, 15 L was higher than other experimental precinct.

• 한국수산과학회지
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• 제20권6호
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• pp.489-500
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• 1987

파랑볼우럭, Lepomis macrochirus의 생식주기성립기구를 밝히고저 자연을 대상으로, 생식주기를 비롯하여 산란횟수, 군성숙도 및 포란수를 조사하였고 이를 토대로 생식소의 활성과 퇴화 그리고 재성숙에 미치는 수온 및 광주기의 영향을 실험적으로 밝혔다. 1. 자연산 생식년주기는 수온이 상승하며, 일장이 결어지는 3월부터 성장하기 시각하며, 6월에는 완숙기가 되고 7월에 산란성기를 이룬다. 이후 년중최고 수온기이며 일장이 짧아지는 8월부터 생식소는 퇴화 되어 휴지기로서 월동한다. 2. 춘계생식소의 활성화에는 고수온($15^{\circ}C$이상)과 장일광주기(14 L 이상)의 복합적 작용이 필요하다. 3. 생식소의 성숙에는 14 L 이상의 장일광주기가 유지되어야 하며 이때 수온상승은 보상적으로 작용한다. 4. 생식소퇴화는 고수온($25^{\circ}C$이상)에 의해 초래되며 일장의 단일화가 촉진적 역할을 한다. 5. 산란기를 마치고 휴지기에 접어든 개체도 장일광주기(15 L)에서 재성숙되고 있어, 이들 생식주기는 인공적으로 제어가 가능함을 시사해 준다.