• 한국발생생물학회지:발생과생식
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• 제23권4호
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• pp.323-331
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• 2019

In this study, an experiment was conducted to investigate the annual reproductive cycle of a Korean flat bittering, Acheilognathus rhombeus, from Ogok-myeon located in Seomjin River. The reproductive cycle was examined histologically regarding water temperature and day length of the habitat, the gonadosomatic index (GSI), and developmental characteristics of female and male gonads. The maximum GSI was found to be 3.50±0.53 and 1.36±0.14 for females and males, respectively, when the water temperature and day light was 16.9℃ and 11.3 hours, respectively in October 2018. On the other hand, the minimum GSI was found to be 0.16±0.09 and 0.69±0.15 for males and females in December 2018 and February 2019, respectively. The ovipositor of females appeared from August to November 2018. We compared and calculated the stages of germ cell developmental characteristics in the testis and ovaries to determine the reproductive cycle. According to the result, we classified the female A. rhombeus reproductive cycle into four phases, which are ripe and spawning phase (October), degenerative phase (November to December), growing phase (January to March) and mature phase (April to September). The annual reproductive cycle of male A. rhombeus was categorized into four phases: mature phase (June to October), degenerative phase (November to March), resting phase (April) and growing phase (May). The Korean flat bittering is an autumn-spawner as the main spawning season in October. In male, testicular spermatogonia appeared all year-round, and the ripe and releasing phase, which is characteristics of the spawning season in other fish, did not appear.

• 환경생물
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• 제33권4호
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• pp.419-424
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• 2015

두꺼비 (Bufo gargarizans)의 난소주기를 파악하기 위해 암컷 성체를 대상으로 gonadosomatic index (GSI)와 난소 내 여포난자의 크기와 난황 축적 정도를 기준으로 발달과정을 연중 조사하였다. 4월에는 난소 무게와 GSI가 가장 낮게 나타났으며 모든 여포난자들은 난황 축적 전단계의 상태로 존재하여 난황 형성이 중단된 것으로 판단된다. 난소 무게와 GSI가 증가하기 시작한 5월의 난소에서는 난황 축적 전기단계의 여포난자가 출현하였고 6월에는 난황 축적 중기단계와 난황 축적 전단계의 여포난자가 존재하여 난소 무게와 GSI도 증가하여 나타났다. 이러한 현상은 이 시기에 난황 축적현상이 진행되는 것을 의미하며 난소 무게와 GSI가 급격히 증가하기 시작한 9월에는 난황 축적 중기단계의 여포난자들과 난황 축적이 거의 완성된 난황 축적 후기단계의 여포난자들이 존재하였다. 난황 축적을 마치고 성장이 완료된 여포난자들은 10월부터 일부 출현하기 시작하여 동면기인 12월에 급격히 증가하였으며 2월의 난소에서는 성장이 완료된 여포난자가 전체적으로 존재하여 여포난자의 성장기에는 난소 내의 모든 여포난자들이 동시적 (synchronized)으로 진행되지 않고 각각의 여포난자에 따라 진행되다가 배란시기에 성장이 완료된 상태를 유지하는 난소주기를 나타내었다.

• 한국환경생태학회지
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• 제28권3호
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• pp.287-292
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• 2014

한국산개구리(Rana coreana)의 난소주기를 파악하기 위해 암컷 성체를 대상으로 gonadosomatic index(GSI)와 난소 내 여포난자의 크기와 난황축적 정도를 기준으로 발달과정을 연중 조사하였다. 난소무게와 GSI는 3월부터 5월까지 가장 낮게 나타났으며 모든 여포난자들은 난황축적 전단계의 상태로 존재하여 난황형성이 중단된 것으로 판단된다. 난소무게와 GSI가 증가하기 시작한 6월의 난소에서는 난황축적 전기단계의 여포난자가 출현하였고 8월에는 난황축적 중기단계와 난황축적 전단계의 여포난자가 존재하여 난소무게와 GSI도 증가하여 나타났다. 이러한 현상은 이 시기에 난황축적 현상이 활발하게 진행되는 것을 의미하며 난소무게와 GSI가 높게 나타난 9월에서 11월까지는 난황축적 중기단계의 여포난자들과 난황축적이 거의 완성된 난황축적 후기단계의 여포난자들이 존재하였다. 동면중인 12월부터 난황축적을 마치고 성장이 완료된 여포난자들이 출현하였으며 2월의 난소에서는 성장이 완료된 여포난자가 전체적으로 존재하여 여포난자의 성장기에는 난소내의 모든 여포난자들이 동시적(synchronized)으로 진행되지 않고 각각의 여포난자에 따라 진행되다가 배란시기에 성장이 완료된 상태를 유지하는 난소주기를 나타내었다.

• 한국양식학회지
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• 제15권1호
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• pp.43-48
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• 2002

We investigated the gonadosomatic index (GSI), germ cell development, reproductive cycle of the Afriean lungfish Protorierus annecteus (Owen) by histological observations and morphometric data. Samples were collected from the river Orie and its flood of Nigeria, from January to December 2000. The fish is dioecious and oviparous. Monthly changes in the gonadosomatic index (GSI) showed a similar pattern to change in the mean oocyte diameter and the reproductive cycle. The reproductive period occurred from March to July-August; the spawning period was once a year between truly and August, and the main spawning occurred in August when active and voracious feeding occurred during the rainy season. In the resting (dormant) stage after spawning, fish stopped feeding and aestivated during the dry season from December to February. The reproductive cycle of the species can be divided into five successive stages, quiescent stage (March to April), developing/maturing stage (April to lune), ripe/spawning stage (July to August), post-spawning stage (September to November), and resting (dormant) stage (December to February).

• 수산해양기술연구
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• 제45권4호
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• pp.287-291
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• 2009

This study examined the maturation and main spawning season of Japanese spear lobsters, Linuparus tirgonus(Von Siebold) captured around Jeju island from January to September, 2008. Carapace length(CL), body weight(BW) and gonad weight(GW) were measured. Gonadosomatic index(GSI) and sex ratio were calculated. In female group, CL showed the highest value in June and decreased after August. GW showed a peak in July and decreased rapidly after August. The mean gonadosomatic Index(GSI) reached a maximum value between June and August. Number of egg ranged from 143,360 to 189,504.

• 한국수산과학회지
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• 제37권3호
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• pp.226-231
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• 2004

Maturation and spawning of Acentrogobius pflaumi were studied using samples collected from the Gwangyang Bay, Korea, from January to December, 1999. The gonadosomatic index (GSI) of the female was the highest in May. The spawning season lasted from May to June. There was a significant difference in the 1 : 0.59 sex ratio between males and females (p<0.01). The percentage of sexually mature females was over $50\%$ for the size group between 4.5 cm and 4.9 cm, and $100\%$ for the size group over 5.5 cm in body length. The size of eggs spawned was between 0.4 to 0.6 mm, and the spawning occured once a year. Fecundity varied between 3,600 and 9,700 eggs. The relationship between the fecundity and body length of the fish was expressed in the fecundity equation as; $F=0.294{\times}10^3\;BL^{1.899}.$ The first spawning length was 4 cm BL.

• 한국가축번식학회지
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• 제16권3호
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• pp.247-260
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• 1992

This study was carried out to investigate the histomorphological changes of ovaries obtained from 100 of 1-year-old female Korean loach(misgurnus anguillicaudatus). The light microscopic and ultrastructural changes ofooplasm and follicular membranes of oocytes, were observed by lightand transmission electron microscope during the reproductive cycle. All data were collected from November in 1991 to May in 1992. The results obtained in this study were as follows: The size of the nucleoli and number of the yolk granules increased as the oocytes grown. Yolk granules were loosely deposited in the oocytes as crystalline granules. Due to the presence of large early and late maturing oocytes, their ovaries were enlarged, transparent, granular and yellowish in color. The lattice was broken down at hydration, leaving the egg transparent. As the percentages of fish in LMO and RO stage increased from March to April, mean gonadosomatic index(GSI) values(18.49%) increased. Zona radiata change a squamous into cuboid shape in EMO stage. Processes from the granulosa cells and from the oocyte, microvilli grow and make contact with other in the pore canals of the zona radiata during vitellogenesis, but are withdrawn as the zona radiata becomes more compact and devoid of pore canals during oocyte maturation. Seasonal changes in the microscopic appearance of the ovaries were well correlated with those in both GSI and macroscopic appearance.

• 수산해양기술연구
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• 제54권4호
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• pp.353-359
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• 2018

Basic reproductive biology of the daggertooth pike conger, Muraenesox cinereus were investigated based on the samples from August 2015 to December 2017 in Korean waters. A total of 2,328 samples was collected (1,593 females and 735 males) during the study period. The mean anal lengths (AL) were $33.5{\pm}9.2cm$ in females and $26.2{\pm}7.3cm$ in males respectively. The females were larger than males in AL (p < 0.05). Sex ratio was 2.2:1 in female to male (p < 0.05). The gonadosomatic index (GSI) varied monthly. GSI of female reached the maximum in July 2016 and June 2017 and the minimum in October 2016 and September 2017 respectively. The spawning period was from June to October. The size at sexual maturity ($L_{50}$) of females was estimated at 24.9 cm in AL (63.5 cm in TL).

• 생명과학회지
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• 제19권12호
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• pp.1851-1854
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• 2009

본 연구는 통영 해역에서 채집되어진 갯장어, Muraenesox cinereus의 생식년주기에 있어서 난소 발달과 생식소중량지수 (gonadosomatic index; GSI) 변화에 따른 혈중 estradiol- $17{\beta}$ ($E_2$) 농도 변화를 서로 연관시켜 조사하였다. 난소 성숙도는 조직학적 관찰을 기초로 주변인기(11월-2월), 유구기(3월-4월), 초기 난황형성기(4월-5월) 및 후기 난황형성기(6월-10월)로 나 눌 수 있었다. GSI의 계절적 변화는 수온과 밀접한 연관성을 가지고 있으며, 난소의 성숙 정도에 영향을 미쳤다. 혈중 $E_2$ 농도는 GSI 변화와 관련이 있어 4월에 증가하여 7월에 년중 최고치에 도달하였고 10월까지 비교적 높은 농도로 유지하였다. 이러한 결과들은 GSI와 혈중 $E_2$ 농도 변화는 갯장어 난소 발달과 밀접한 관련이 있음을 나타내고 있다. 그러나 본 연구에서는 산란기의 암컷 갯장어를 채집하지 못하였다. 이러한 이유로 산란기의 개체는 외해의 심해쪽으로 이동하기 때문이라고 추측된다.

• 한국발생생물학회지:발생과생식
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• 제16권2호
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• pp.87-93
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• 2012

박대 생식소중량지수(gonadosomatic index, GSI)의 월간 변화는 2월에서 7월까지는 아주 낮은 값을 보였으나, 8월부터 생식소가 급격히 발달하기 시작하여 9월에 최고값을 나타내었다. 이후 10월부터 점차 낮아져 11월에 다시 낮아지는 경향을 보였다. 비만도(condition factor, CF)의 월간 변화도 9월에 최대값을 보였다. 간중량지수(hepatosomatic index, HSI)의 월간 변화는 6월에 최대값을 보인 후 7월에 급격히 낮아져 최저값을 보인 후 9월부터 증가하기 시작하여 11월에 최대값에 도달하였다. 난소발달은 미성숙기(2~7월), 초기 성숙기(7월 말), 성숙기(8월), 후기 성숙기(8월 말), 완숙 산란기(9~10월), 회복 휴지기(11월)의 6단계로 구분되었다. 박대의 포란수를 조사한 결과, 총 포란수(fecundity, F)와 전장(total length, TL)과의 관계는 $F=251.43TL^{0.1264}$($r^2$=0.4027)이었으며, 총 포란수와 체중(body weight, BW)과의 관계는 F=1130.4BW-880848($r^2$=0.677)로 나타났다. 박대 암컷의 50%가 성숙하는 전장은 46.87 cm로 조사되었다.