• 한국발생생물학회지:발생과생식
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• 제21권3호
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• pp.297-305
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• 2017

An experiment was conducted to investigate the annual reproductive cycle of a Korean endemic species, Acheilognathus majusculus, from Jeokseong-myeon located in Seomjin River. The reproductive cycle is examined histologically regarding water temperature and day length of the habitat, the gonadosomatic index (GSI), the female ovipositor length index (OLI), monthly variation in egg diameter distribution, and developmental characteristics of female and male gonads. The maximum GSI was found in $19.21{\pm}2.32$ and $6.90{\pm}0.53$ for female and male respectively when water temperature ($14^{\circ}C$) and day length (11.1hr) began to rise. On the other hand, the minimum level was reached during August ($1.87{\pm}0.67$ for female and $0.88{\pm}0.50$ for male). No samples represent with measurable ovipositor between September and November, while the longest ovipositor length index was in April ($79.68{\pm}4.69%$). We compared and calculated the stages of testis and ovary development process in order to determine the germ cell development characteristics and the reproductive cycle. According to the result, we classified the female Acheilognathus majusculus reproductive cycle into four stages: Ripe (April) and spawning phase (May to June), degenerative phase (July), growing phase (August to December), and mature phase (January to March). The annual reproductive cycle of male Acheilognathus majusculus was categorized into five stages viz. Ripe and spawning phase (May to June), degenerative phase (July to August), resting phase (September to November), growing phase (December to February), and mature phase (March to April).

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2004년도 춘계학술발표대회
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• pp.257-257
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• 2004

The study was carried out to investigate the effects of morphology, reproductive cycle, incubation time and activation of oocytes on in vitro maturation of cat oocytes and development of IVM/IVF embryos. 1. When recovered from ovaries collected at different stages of the reproductive cycle (inactive, follicular and luteal stage), the developmental rates of oocytes to GV and MI stage were 72.5% and 27.5%, 57.5% and 7.5%, 62.5% and 17.5%, respectively. (omitted)

• 한국발생생물학회지:발생과생식
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• 제17권4호
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• pp.353-361
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• 2013

The objective of this study was to characterize the reproductive cycle of the chameleon goby, T. trigonocephalus. Gonadal development was investigated using a histological method. Specimens were collected monthly, from April 2009 to March 2010. The gonadosomatic index (GSI) of females began to increase in April, reaching the maximum in May, and declined sharply in August. In males, the GSI began to increase in April and reaching the maximum in July. The annual reproductive cycle of T. trigonocephalus can be divided into four successive stages in females: the growing (November-March), maturing (April-May), ripe and spawning (June-July), and recovery (August-October) stages. Males passed through growing (November-March), maturing (April-June), ripe and spermiation (July-August), and recovery (September-October) stages. These results indicate the spawning season is from June to July. The relationship between fecundity (Fc) and body length (BL) was $Fc=86.1511BL^{2.6506}$. Fecundity was ranged from 3,448-9,654 eggs in a BL of 4.8-7.2 cm and it was increased as BL increased.

• 한국발생생물학회지:발생과생식
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• 제22권1호
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• pp.1-8
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• 2018

The annual reproductive cycle of the Korean endemic slender catfish, Silurus microdorsalis, was examined histologically regarding water temperature and day length of habitat, gonadosomatic index (GSI), and development characteristics of female and male gonads. The maximum GSI value was found in May, $1.23{\pm}0.33$ and $11.77{\pm}3.23$ for male and female respectively (habitat water temperature $21.5^{\circ}C/13.59hr$ day length). On the other hand, the minimal level was $0.63{\pm}0.10$ in July ($26.5^{\circ}C/14.17$) for male and $1.36{\pm}0.08$ in October ($20^{\circ}C/11.2hr$) for female. We compared and calculated the stages of testis and ovary development process in order to determine the germ cell development characteristics and the reproductive cycle. According to results, we classified the annual reproductive cycle of the slender catfish into five stages: Growing phase (December-February), Mature phase (March-April), Ripe and spawning phase / Releasing phase in male (May-June), Degenerative phase (July-August), and Resting phase (September-November).

• 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.

• Reproductive and Developmental Biology
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• 제28권1호
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• pp.53-57
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• 2004

The study was carried out to investigate the effects of morphology, reproductive cycle, incubation time and activation of oocytes on in vitro maturation of cat oocytes and development of IVM/IVF embryos. The results were summarized as follows: 1. When recovered from ovaries collected at different stages of the reproductive cycle (inactive, follicular and luteal stage), the developmental rates of oocytes to GV and MI stage were 72.5% and 27.5%, 57.5% and 7.5%, 62.5% and 17.5%, respectively. 2. The developmental rates of oocytes with cumulus cells to GV and MI stage in different conditions of incubation (5% $CO_2$ , 95% $O_2$ and 10% $CO_2$, 90% $O_2$) were 70.0% and 27.5%, 52.5% and 20.0%, 55.0% and 12.5%, respectively. 3. The developmental rates to GV and MI oocytes when cultured at different time of incubation (17∼20, 21∼24, 25∼28 and 29∼32 h) were 67.5% and 20.0%, 67.5% and 30.0%, 62.5% and 22.5%, 65.0% and 15.0%, respectively. 4. The fertilization and cleavage rates of freshly collected oocytes with and without cumulus cells were 72.5% and 25.0%, 37.5% and 7.5%, respectively. The rates were greater in oocytes with cumulus cells than those without cumulus cells. 5. The fertilization and cleavage rates of oocytes recovered from ovaries collected at different stages of the reproductive cycle (inactive, follicular and luteal stage) were 75.0% and 25.0%, 40.0% and 7.5%, 50.0% and 15.0%, respectively.

• 한국어업기술학회:학술대회논문집
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• 한국어업기술학회 2001년도 추계 수산관련학회 공동학술대회발표요지집
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• pp.317-318
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• 2001

In crustacea the molting cycle is the most important physiological process affecting growth, behaviour, reproduction and population dynamics through their life span. Particularly molt cycle is closely related to reproductive cycle, and it is important to determine the successive stages of molt cycle to understand reproductive phenomena including ovarian cycle and the development of the embryos in the marsupium. (omitted)

• 한국수산과학회지
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• 제39권6호
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• pp.472-479
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• 2006

The sexual maturity and reproductive cycle of the common squid, Todarodes pacificus captured from the East Sea, Korea, between January 2004 and January 2006, were investigated by documenting changes in the gonadosomatic index (GSI), gonad development, and oocyte size frequency distribution. The GSI of females began to increase in July, reached a maximum in August, and then gradually decreased. The GSI of males increased from July to March. Using gonad histological observations, we identified four oocyte developmental stages. The changes in GSI and gonad tissue resulted in the classification of the annual reproductive cycle into the following four successive stages: immature (April to June), growing (June to July), mature (July to August), and ripe and spawning (August to March). According to the oocyte diameter size frequency distribution in the ovary, this species appeared to have asynchronous oocyte development and one spawning time.

• 한국발생생물학회지:발생과생식
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• 제4권2호
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• pp.175-180
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• 2000

양산 내원사 계곡에 서식하는 난태생인 다슬기(Semisulcospira libertina libertina)를 재료로 하여 번식주기를 조사하였다. 서식지 수온은 연중 1.3~22.5$^{\circ}C$였으며, 육중량비는 수온이 상승하기 시작하는 3월에 최고값을 보였고, 8월에 최저값을 나타내었다. 난모세포의 평균 직경은 7월에 249.6$\pm$2.6 $mu extrm{m}$로 최대값을 나타냈으며, 12월에 134.3$\pm$2.8 $\mu\textrm{m}$로 연중 최소값을 보였다. 다슬기는 혹서기와 혹한기를 제외하고 주년 번식하는 종으로서, 연간 2회의 주된 번식주기를 가져, 암컷에서 분열증식기 3월ㆍ10월, 성장기 4~5월ㆍ11월, 성숙기 6~7월ㆍ12월, 배란기 8월ㆍ1월, 출산기 9~10월ㆍ3~5월, 휴지기 9월ㆍ2월, 수컷에서는 분열증식기 3월ㆍ10월, 성장기 4월ㆍ11월, 성숙기 5~6월ㆍ12월, 교미기 7~8월ㆍ1월, 휴지기 9월ㆍ2월인 것으로 판정되었다.

• 한국수산과학회지
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• 제33권3호
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• pp.184-191
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• 2000

포항 형산강 하구에 서식하는 참재첩, Corbicula leana을 대상으로 생식세포 형성과정 및 생식주기를 조직학적으로 조사하였다. 참재첩은 자웅이체로서 난생이며, 생식소는 완숙하면 암컷은 흑갈색, 수컷은 유백색을 띤다. 생식소관은 내장낭의 간중장선 하방으로 부터 근충의 외벽근층내에 있는 섬유성 망상결체조직까지 분포되어 있다. 난소는 수지상으로 연결된 난소소관으로 구성되어 있고, 정소 역시 많은 소관상의 정소소관으로 구성되어 있는데 이들 소관의 내강상피가 생식상피 기능을 하고 있다. 성숙난모세포는 배포의 변화로 알 수 있으며, 그 크기는 $70{\~}80{mu}m$ 정도이다. 난소 및 정소의 초기 발달에는 간충조직과 색소과립세포들이 영양세포로 관여하고 있으며 난소와 정소가 발달하면서 점차적으로 사라진다. 생식소 발달은 수온과 밀접한 연관성이 있고, 비만도의 변화도 주기성이 일치하였다. 생식주기는 분열증식기, 성장기, 성숙기, 방출기, 퇴화기 그리고 회복기 둥의 연속적인 주기로 구분할 수가 있다. 산란기는 6월 하순부터 9월 중순까지이고, 산란성기는 7월과 8월이었으며 생물학적 최소형은 10.0 mm 이상으로 조사되었다.