• 한국어류학회지
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• 제21권2호
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• pp.93-99
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• 2009

본 연구는 전남바다목장 해역 내에 서식하는 감성돔의 성숙과 산란에 관한 연구로, 2007년 3월부터 2008년 2월까지 낚시어업에 의해 어획된 시료를 대상으로 수행하였다. 감성돔의 50% 성전환 체장은 26.7 cm로 추정되었고, 암컷의 생식소 발달과정 및 생식소중량지수(GSI) 월변화로부터 감성돔의 산란기는 3~7월, 주 산란기는 5~6월로 추정되었다. 포란수는 최소 39,596립(체장 32.2 cm)에서 최대 2,894,913립(체장 42.0 cm)으로 계수되었고, 체장(FL)과 포란수(F)간의 관계식은 $F=1.264FL^{3.869}(R^2=0.736)$으로, 일반적 경골어류에서와 같이 체장이 커질수록 포란수도 증가하는 경향을 보였다. 산란에 참여하는 50% 군성숙도 체장은 암컷은 25.8 cm, 수컷은 19.0 cm이다.

• 한국발생생물학회지:발생과생식
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• 제25권4호
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• pp.269-277
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• 2021

Effects of water temperature and hormones on ovarian development of conger eel in Korea were investigated. Ovarian development was analyzed by measuring gonadosomatic index (GSI) and oocyte diameter with histological methods. At rearing water temperatures of 12℃, 14℃, and 16℃, GSI value increased from 3.66 at the start of the experiment to 7.44, 8.82, and 7.34 at the end of the experiment, respectively. At rearing water temperatures of 12℃, 14℃, and 16℃, egg diameter increased from 245.11-300.25 ㎛ at the start of the experiment to 377.62-480.27 ㎛, 396.72-498.54 ㎛, and 382.29-475.69 ㎛ at the end of the experiment, respectively. Follicular oocyte development revealed that primary yolk globule stage observed from January to March. It entered to secondary yolk globule stage in April and remained at the same stage until July. As a result of examining effects of three hormones (human chorionic gonadotropin (HCG), luteinizing hormone releasing hormone analogue (LHRHa), and salmon pituitary extraction (SPE) on ovarian development, HCG was found to be the most effective one. The progress from diapause of the secondary yolk globule stage to migratory nucleus stage of oocytes could be induced by treating fish with HCG at 1,000 IU/kg. The effect of hormone treatment on ovarian development of conger eel in Korea was the most effective at water temperature of 14℃.

• 한국발생생물학회지:발생과생식
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• 제22권4호
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• pp.369-378
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• 2018

We determined the morphologic characteristics (body weight and degree of abdomen inflation) of the red spotted grouper, Epinephelus akaara, mother fish producing healthy eggs. Experimental fish were chosen from fish reared in a sea cage. The fish were divided into four size groups by body weight: 400~600, 600~800, 800~1,000, and 1,000~1,200 g and four stages (I~IV) of the degree of abdomen inflation. After hormone treatment, we observed the amount of ovulation-induced eggs, and rates of buoyancy, fertilization, embryonic survival, and hatching. As a result, mother fish with a body weight of 600 g or more spawned, and the fertilization rate, embryonic survival rate, and hatching rate were high in the 800~1,000 g range, thus showing effective ovulation induction. As a result of dividing the degree of abdomen inflation based on the anal fin of the mother fish into I-IV stages and determining hormone treatment time, the GSI was $0.9{\pm}0.2%$ at stage I, $2.3{\pm}0.2%$ at stage II, $5.6{\pm0.2%$ at stage III, and $7.9{\pm}0.9%$ at stage IV. The flotation rate and hatching rate were highest at stage III, and the fertilization rate and embryonic survival rate were highest at stage IV. Therefore, in terms of egg quality, the amount of eggs collected per mother fish, maturation, and histology were different depending on the degree of abdomen inflation. At stage III, where the abdomen inflation degree of the mother fish was based on the basal part of the dorsal fin relative to the height of the anal fin was 1, the egg quality was highest.

• 한국해양생명과학회지
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• 제7권1호
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• pp.37-44
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• 2022

연구는 기름가자미의 성비, 군성숙도 및 주 산란기에 관한 정보를 얻기 위해 수행하였다. 성비(암:수)는 1:0.54 (n=189:103, 암컷 64.7%)였으며, 전장이 증가함에 따라 암컷의 비율이 높아지는 경향을 보였다. 난모세포 발달패턴은 동일 난소 내에서 여러 단계의 난모세포군이 확인되는 난군동기발달형이었다. 로지스틱 회귀모델에 의해 분석된 50% 성숙 전장은 암, 수 각각 28.51 cm과 30.49 cm였다. GSI는 암, 수 각각 4월과 3월에 가장 높았으며, 주 산란기는 4-5월로 분석되었다.

• Fisheries and Aquatic Sciences
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• 제25권1호
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• pp.12-19
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• 2022

In the present study, we investigated the effects of recombinant eel gonadotropins (rec-GTHs) on maturation induction in immature ovarian culture in vitro and sex steroid hormones in vivo in the Japanese eel Anguilla japonica. To study the in vitro effects of rec-GTHs on estradiol-17β (E2) production in immature ovarian tissues, ovarian tissues were incubated with different doses of rec-follicle-stimulating hormone (rec-FSH) or rec-luteinizing hormone (rec-LH). The results revealed that the E2 levels in the rec-FSH (0.1, 0.5, or 1 ㎍/mL)- and rec-LH (0.1 or 0.5 ㎍/mL)-treated groups were significantly higher than those in the female eels from the control group. Furthermore, to investigate the in vivo effects of rec-GTHs on the gonadosomatic index (GSI) and plasma sex steroid hormone levels, the eels were injected intraperitoneally with eel's ringer (control), salmon pituitary extract (SPE; for female eels), human chorionic gonadotropin (hCG; for male eels), rec-FSH, rec-LH, and rec-FSH + rec-LH once a week. The results revealed that except for the SPE and the hCG groups, none of the groups exhibited a significant difference in GSI values. However, in vivo plasma E2 levels increased at the end of 4 weeks after rec-FSH treatment in female eels. Based on these results, it is suggested that rec-GTHs may have a positive effect on sexual maturation in female eels; however, further studies on complementary rec-protein production systems and additional glycosylation of rec-hormones are needed to elucidate hormone bioactivity in vivo and in vitro.

• 한국수산과학회지
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• 제55권6호
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• pp.927-937
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• 2022

The reproductive characteristics of Pacific anchovy, Engraulis japonicus were investigated using samples randomly collected from the southern waters of Korea between January and December 2021. We analyzed monthly changes in maturity stages, gonadosomatic index (GSI), egg diameter, fecundity, and fork length (FL) at sexual groups maturity of 50%, 75% and 97.5%, and sex ratio (female:male). GSI value showed two peaks in May and August; however, microscopic analysis of E. japonicus gonad tissue revealed that the spawning period was from March to October. The main spawning seasons for the entire populations were from April to June and August to September. The overall sex ratio was female-biased (1 females, 0.89 male). The fecundity (F) of female anchovies ranged from 429 eggs at an FL of 8.0 cm to 13,824 eggs at an FL of 14.9 cm and the relationship between FL and F was 0.0788FL^4.422. The FL at 50% group maturity was 8.26 cm for female anchovies. Based on the results, we suggest that the reproductive cycle in Pacific anchovies may be related to pulses in water temperature and the sexual cycle of the fish.

• 한국수산과학회지
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• 제56권3호
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• pp.315-323
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• 2023

The maturity and spawning of the large yellow croaker Larmichthys crocea were investigated using samples randomly collected in the Jeju coastal area, Korea. We analyzed monthly changes in maturity stages, gonadosomatic index (GSI), and egg diameter. Additionally, we verified fecundity by size class and total length (TL) at sexual group maturity at 50%, 75%, and 97.5%, as well as by sex ratio (female vs. male). The overall sex ratio of females to males was 1:0.42. The GSI values showed a peak in October, but the spawning season, revealed by the microscopic analysis of gonadal tissue of L. crocea was from October 2021 to March 2022, with the main spawning period from October to November. The fecundity (F) of female L. crocea ranged from 39,232 eggs at 20 to 29.9 cm to 251,003 eggs at 50 to 59.9 cm, with the relationship between TL and F being 80.244TL-1641.6. In females, TL at 50%, 75%, and 97.5% maturity was 22.4, 24.3, and 29.0 cm, respectively.

• 한국수산과학회지
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• 제56권5호
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• pp.667-675
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• 2023

The Spanish mackerel Scomberomorus niphonius is an economically important fish species in the southwestern waters of Korea. This study aimed to provide insights into the reproductive biology of this species in the southwestern waters of Korea. We analyzed monthly changes in fork length (FL), maturity stages, and gonadosomatic index (GSI). Moreover, we measured the in FL at sexual group maturity of 50%, 75%, 97.5%, and sex ratio (female vs. male). The overall sex ratio of female and male was 1:0.8. GSI value showed the highest peak in May; however, the spawning period revealed by the microscopic analysis of gonad tissue of S. niphonius was from April to August 2020. The main spawning seasons for the entire populations was from May to June. The fork length at 50% group maturity was 53.3 cm for females and 53.1 cm for males. These results of spawning period of Spanish mackerel highlight the influences of water temperatures that were higher than those in the past, an increase in resource levels, and the level of Pacific anchovy resources flowing into the spawning ground.

• 한국수산과학회지
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• 제18권3호
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• pp.253-261
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• 1985

부산근해산 문치가자미, Limanda yokohamae를 대상으로 1983년 12월부터 1984년 11월까 주년에 걸쳐 생식소숙도지수(GSI)의 연간변화를 비롯하여 배우자형성과정 및 생식연주기를 조사하였고 아울러 난경조성에 의한 산란기간에 개체당 산란회수, 생식주기와 관련하여 간숙도지수(HSI)와 비만도변화 등을 조사함으로써 생식주기성립기구를 고찰하였다. GSI는 일장이 단일화되며 수온이 하강되는 추계에 상승하기 시작하여 연중 최저수온과 최단일인 12월에 최대치를 나타낸다. 배우자는 6월부터 생식소가 활성화되어 난원세포 및 정원세포의 활발한 분열증식이 일어나며, 10월에 성숙기에 이르고, 12월에 완숙되어 12월하순부터 1월에 걸쳐 산란기를 가진다. 산란후 2월부터 5월까지 생식소는 퇴화${\cdot}$위축된 상태로 휴지기를 갖는다. 한 산란기동안 개체들은 1회 산란을 한다. 난모세포가 난황을 활발하게 축적하기 시작하는 난황구기부터는 간으로 부터 합성된 Vitellogenin을 공급받는 것으로 간주되며, 방란${\cdot}$방정에 의한 체력소모가 큰 것으로 나타났다. 본 문치가자미는 전형적인 동계산란종으로 단일광주기와 저수온이 생식세포형성 및 난모세포의 성숙촉진에 직접 관여하며, 배란 역시 이들 환경요인과 깊은 관계가 있는 것으로 생각된다.

• 한국양식학회지
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• 제9권3호
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• pp.205-213
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• 1996

한국산 메기의 경제적이고 효율적인 산란유도를 위한 연구로써 GnRH-a의 이용가능성에 대하여 검토하여 다음과 같은 결과를 얻었다. GnRH-a 처리된 메기의 산란유도율은 어체중 kg당 70 ${\mu}g$에서 $67\%$, 90 ${\mu}g$에서 $86\%,\;120{\mu}g$이상에서는 $100\%$로 나타났다. 호르몬 주사후 산란이 유도되기까지 대체로 $22\~25$시간이 소요되었다. 생식소중량지수(GSI)는 $100\%$의 산란유도율을 보인 120 ${\mu}g/kg$처리된 그룹에서 $23\~30\%$를 pseudo-GSI는 $18\~21\%$로 비교적 높고 고른 분포를 나타냈으며, 산란된 난의 수는 어체중 kg당 $58,000\~65,000$개 였다. 또한 수정률 및 부화율은 각각 $94\%$와 $81\%$로 나타났다. GnRH-a 처리에 따른 뇌하수체의 미세구조적 변화를 관찰한 바, 호르몬 주사전 성숙한 암컷 메기의 생식소자극호르몬 분비세포(gonadotrops)는 전자밀도가 높은 $150\~300$ nm 크기의 수 많은 소과립과 $800\~1000\;nm$의 전자밀도가 다소 낮은 소수의 대과립의 존재가 관찰되었다. 한편 호르몬주사후의 gonadotrops에서는 대소 과립들의 현저한 소실과 rER의 현저한 증가가 관찰되었는데, 이는 GnRH-a에 의해 생식소자극호르몬의 대량방출을 시사하는 것이다. 이상의 결과로부터 GnRH-a의 사용은 기존의 HCG 및 잉어뇌하수체 분말보다 적어도 $2\~3$ 배이상의 비용절감을 가져와 메기의 인공 종묘 생산에 매우 효과적이고 경제성이 있는 것으로 나타났다.