• The Korean Journal of Malacology
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• v.19 no.2
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• pp.117-124
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• 2003

Reproductive cycle and sex ratio of the marsh clam Corbicula japonica, a oviparous clam, were investigated monthly by histological observation. Samples were collected in brackish water of Namdae stream on the east coast of Korea from November 2000 to October 2001. It was able to devide the reproductive cycle of this species into five successive stages; early active (April to June), late active (May to June), ripe (June to August), partially spawned (June to September), spent (September to January) and resting stage (February to April). The spawning period was from July to September, and the main spawning occurred between August and September when seawater temperatures reached above 26$^{\circ}C$. Mature eggs of Corbicula japonica were 60-70 ${\mu}m$ in diameter. The sex ratio of individuals over 10.1 mm in shell length was about 1:1 (x$^2$ = 1.22, p > 0.05).

• Korean Journal of Fisheries and Aquatic Sciences
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• v.34 no.6
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• pp.656-660
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• 2001

Gametogenesis, the reproductive cycle, and the condition index of the soft clam, Mya arenaria were investigated monthly based on histological observation at Sachon Bay, south coast of Korea from May 1998 to September 1999 . M. arenaria is dioceious. The ovary and testis were composed of a number of ovarian sacs and testicular tubules, respectively. Ripe oocytes were characterized by germinal vesicles with nucleoli, and their sizes about $60{\mu}m$ in diameter. Monthly changes in condition index and water temperature were closely related to the annual reproductive cycle. The reproductive cycle can be classified into 5 stages: early active stage (february to March), late active stage (April to August), ripe stage (September), partially spawned and spent stage (September to October), inactive stage (November and January).

• Proceedings of the Korean Aquaculture Society Conference
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• 2006.05a
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• pp.656-657
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• 2006

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.6
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• pp.523-528
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• 1984

The small filefish, Rudarius ercodes, generally spawning from mid May to early October in the natural habitat, was exposed to various photoperiod and temperature regimes. These environmental effects on the gonad activity, regression and recrudescence were experimentally investigated based on the mechanism of reproductive cycle. Spawning season was initiated in the early spring with the gonad activated by long photoperiod(13L) and stimulated by compensatory temperature rising. Even when the gonad activated readily at the above critical daylength (12L to 13L)was kept back at the below if, it went on maturing. At the end of spawning period (mid September), since the shortening of daylength (12L) resulted in the gonad regression regardless of temperature, the short daylength might be related to the termination of spawning in situ. When the regressive gonad at the post spawning period was treated by the above 13L: $20^{\circ}C$ condition, it could recrudesce and bring forth even spawning. From this fact, the feasible control of annual reproductive cycle of small filefish was recognized. But even in the long daylength, the temperature above $28^{\circ}C$ was preventive of gonad maturation.

• Journal of Aquaculture
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• v.21 no.4
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• pp.252-258
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• 2008

Gonadal development and reproductive cycle of the ark shell Scarpharca subcrenata were investigated by histological observations. Samples were collected monthly from March 2007 to February 2008 in the Yeoja Bay, Yeosu, Jeollanam-do, Korea. S. subcrenata was dioecious. The gonads consist of a number of oogenic follicle and acinus. Monthly changes in the gonad index reached a maximum in June and a minimum in September. Monthly changes in the condition index reached a maximum in April and a minimum in September. The reproductive cycle of this species can be divided into five successive stages: early active stage (January to April), late active stage (March to June), ripe stage (May to August), spent stage (July to September) and recovery and resting stage (September to March). The main spawning of S. subcrenata occurred in July and August in Yeoja Bay. The sex ratio of female to male was not significantly different from 1:1.

• The Korean Journal of Malacology
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• v.23 no.2
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• pp.165-172
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• 2007

Gonadal development, reproductive cycle and sex ratio of the purplish Washington clam, Saxidomus purpuratus were investigated monthly by histological observations. Samples were collected from May 2006 to April 2007 in the Gangjin Bay of Namhea, Gyeongsangnam-do, Korea. The clams are dioecious. The gonads consist of a number of oogenic follicle and acinus. Monthly changes in the gonad index reached a maximum in April and a minimum in July. Monthly changes in the condition index reached a maximum in June and a minimum in November. The reproductive cycle of this species can be divided into five successive stages: the recovery and resting stage (June to December), early active stage (January to April), late active stage (February to July), ripe stage (March to October), spent stage (April to October). The main spawning of the clam occurred in July and September in Gangjin Bay. The sex ratio of female to male was not significantly different from 1:1.

• The Korean Journal of Malacology
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• v.13 no.1
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• pp.43-54
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• 1997

1994년 1월부터 12월까지 1년간에 걸쳐 우리 나라 서해안 비인만의 조간대에서 채집된 떡조개, Dosinorbis(Phacosoma) japonocus(Reeve)를 대상으로 성숙 및 산란시기를 규명하기 위해 생식소 여포지수(GFI)및 생식소지수(GI)의 월별변화, 생식주기, 월별 난경 조성 및 성비를 조사하였다. 본 종은 자웅이체이고, 생식소는 중장선 하부와 소화맹낭 그리고 섬유성 결체조직과 근섬유에 의해 치밀하게 구성된 외측 근섬유층 사이에 위치하고 있다. 산란기 추정을 위해 조사된 GFI와 GI의 월별변화 양상은 생식주기와 일치하는 경향을 보였다. 난경 55-65$\mu\textrm{m}$인 성숙란들은 젤라틴성 막에 의해 둘러싸여 있다. 본 종의 생식주기는 초기활성기 (12-2월), 후기활성기(2-5월), 성숙기(5-8월), 부분산란기(6-8월)그리고 퇴화 및 비활성기(8-12월)의 연속적인 5단계로 나눌 수 있었다. 산란기는 수온 및 먹이이용 가능성과 밀접하게 관련되어 있는 것으로 보이며, 산란은 수온이 2$0^{\circ}C$ 이상인 6월부커 8월까지 일어났고, 산란성기는 6월과 7월이었다. 산란기는 단지 그 해 하계에만 일어남으로써 1년에 1회의 산란기를 가지나 그 산란 빈도 횟수는 1년에 1회의 산란계절 중 2회 이상 일어나는 것으로 추정된다. 암.수 개체들의 성비는 통계 처리한 결과 1:1(x$^{2}$=0.08, P>0.05)로 나타나 암.수간 성비에 차이가 없었다.

• Journal of Aquaculture
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• v.22 no.1
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• pp.34-41
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• 2009

Gonadal development and reproductive cycle of the granular ark Tegillarca granosa were investigated by histological observations. Samples were collected monthly from January to Decemberry 2002 in the Yeoja Bay of Yeosu, Jeollanam-do, Korea. T. granosa was dioecious. The gonads consist of a number of oogenic follicle and acinus. Monthly changes in the gonad index reached a maximum in June and a minimum in August. Monthly changes in the condition index reached a maximum in July and a minimum in September. The reproductive cycle of this species can be divided into five successive stages: early active stage (March to May), late active stage (April to June), ripe stage (May to July), spent stage (July to August) and recovery and resting stage (September to March). The spawning of T. granosa occurred in July and August in Yeoja Bay. The sex ratio of female to male was not significantly different from 1:1.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.53-53
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• 2003

참가자미, Limanda herzensteini는 가자미목 (Pleuronectiformes), 가자미과 (Pleuronectidae)에 속하며, 우리나라의 동해, 일본의 세토내해 이북, 중국 및 사할린 근해에 분포하는 어종이다. 본 종은 연안정착성 어종으로 동해안에서 낚시 및 저인망 어업에 의해 어획되는 산업적 가치가 큰 고급어종이며, 저수온에 강하여 한류성 해역에서의 양식 가능성이 매우 높다고 할 수 있다. 또한 최근에는 참가자미의 자원량 감소가 두드러지고 있으므로 자원증강이 절실히 요구된다. 이 연구에서는 주 어획지역인 강원도 주문진 인근해역에서 1998년 9월부터 1999년 10월까지 자연산 참가자미의 연간 생식소중량지수의 변화를 조사 하였으며, 조직학적 조사에 의한 생식소 발달과정과 생식주기를 밝혔다. 정소는 정소엽 형태이며, 각각의 정소엽은 여러개의 소낭구조를 가진다. 각 소낭내의 생식세포들은 같은 단계의 발달상태를 보인다. 난소는 원추형의 낭상으로 체강벽에서 연결되는 난소간막에 의해 부착되어 있으며, 내부는 결체성 조직인 다수의 난소박판으로 구성되며, 이곳에서 난원세포가 유래한다. 수컷의 GSI는 1월에 가장 높았으며, 암컷의 GSI는 3월에 가장 높은 값을 보였다. 생식주기는 성장기(6~9월), 성숙기(10~12월), 완숙 및 산란기(1~3월) 그리고 회복 및 휴지기(4~5월)로 나눌 수 있었다. 난모세포의 발달양식은 난군동기발달형에 속하였다.

• Journal of Aquaculture
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• v.17 no.2
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• pp.128-132
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• 2004

Reproductive cycle of the brown sole, Limanda herzensteini was investigated by means of histological methods. The testis showed the presence of seminiferous tubule. The tubule consisted of many testicular cysts, each of which contained numerous germ cells - all at the same developmental stage. The ovary consisted of several ovarian lamellae and the oogonia originated from the inner surface of the ovarian lamella. Oocyte development was group-synchronous. Gonadosomatic index (GSI) of the male and female was the highest in January and March, respectively. Reproductive cycle could be classified into the growing (June-September), maturation (October-December), ripe and spent (January-March), and recovery and resting (April-May).