• 한국수산과학회지
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• 제42권1호
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• pp.48-55
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• 2009

The gonad maturation and spawning of blue crab, Portunus trituberculatus (Miers, 1876) using samples caught by trammer net in the western coast of Korea from January to December. The gonadosomatic index (GSI) showed the highest value of 15.0 in June and lowest value of 1.29 in August. Hepatosomatic index (HSI) showed the lowest in the spawning season from June to July. Thereafter, from August the value started to increase to 5.77 in December, showing an adverse trend against GSI. In the histological studies of the female reproductive organ, the gonad filled with primary oocytes from January to February and secondary oocytes in May. The female gonads mature from June, and mature and immature groups could be distinguished from December to February or March. In August, female developed another cycle of gonad development, showing new primary oocytes in the gonads again. Some of female crabs had receptaculum filled with already active sperm cells in it from March to May. In the time of August to September, almost all the females had the sperm sacs in the receptaculum. From the result, the coupling period estimated from August to September. Total RNA and DNA values of the crabs were highest in May (2.51, $0.57{\mu}g/mg$). The DNA value remained unchanged except for the value in May ($0.09-0.13{\mu}g/mg$). while RNA value was lowest in January ($1.08{\mu}g/mg$). The RAN/DNA ratio was the lowest (6.23%) in May and highest (18.05%) in July. The value of correlations coefficient between body weight and fecundity of the crabs was higher that of between carapace width and fecundity.

• Ocean and Polar Research
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• 제43권4호
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• pp.365-370
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• 2021

Manila clam Ruditapes philippinarum is present at high rates of density in tidal flats in Cheonsu Bay on the west coast of Korea, where clams often exhibit mass mortalities in late summer. We monitored the pathologic condition of clams at Hwangdo tidal flat (HD) to understand the parasitic impacts on clam fitness. Manila clams were fully ripe in July and spawned during August and September, as the histology indicated. The histology revealed that clams in HD tidal flats were heavily infected by the protozoa parasite Perkinsus olseni, as the monthly prevalence ranged from 53% (September) to 93% (August). In addition, Manila clams were co-infected by the metazoan parasite Cercaria tapetis and Parvatrema duboisi with the prevalence of 0-33% and 0-14%, respectively. Massive hemocyte infiltration and subsequent inflammation were commonly observed from the gills of P. olseni infected clams. Clusters of P. olseni trophozoites and heavy hemocyte infiltration were also observed from the female gonad, suggesting that P. olseni interferes with host gonad maturation. The larval trematode occupied almost the entire host gonad, resulting in gonad castration. In addition, Metacercaria of P. duboisi were observed from the subsurface of the mantle. Ray's fluid thioglycollate medium assay (RFTM) indicated that clams collected in August and September contained approximately 4.0×106 P. olseni cells/g gills. Condition Index (CI) declined gradually from spring to early summer, and the decline in CI was interpreted as a consequence of the heavy parasitism, as the parasites drain the host's net energy to be used in somatic growth and gamete production.

• 한국패류학회지
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• 제22권2호
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• pp.143-150
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• 2006

The gonad index, condition index, reproductive cycle and spawning of the pen shell Atrina (Servatrina) pectinata were investigated using samples from the subtidal zone of Nokdo on the Boryeong coastal waters of Korea. Samples were collected monthly by SCUBA divers for one year from January to December, 2001. A. (Servatrina) pectinata is dioecious and oviparous. The spawning season of this species occurred once a year from June to August, with the main spawning occurring between June and July when the seawater temperature was around $20^{\circ}C$. Ripe oocytes were about 60-65 ${\mu}m$ in diameter. The reproductive cycle of this species could be classified into five successive stages; early active stage (November to March), late active stage (February to May), ripe stage (April to July), partially spawned stage (June to August), and spent/inactive stage (August to October). Monthly changes in the gonad index reached a maximum (4.6) in May (ripe stage), thereafter, the GI values gradually decreased from June to August when spawning occurred continuously. Therefore, monthly changes in the GI values showed a similar pattern to the gonadal phase. The condition index (CI) of the meat part without the posterior adductor muscle reached the maximum in June (ripe and partially spawned stage) and the minimum in September (spent/inactive stage), Accordingly, monthly changes in the condition indice of the meat part without the posterior adductor muscle coincided with the gonadal phases.

• 한국패류학회지
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• 제26권3호
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• pp.201-209
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• 2010

인위적인 가온만으로도 새꼬막의 성숙 및 정상적인 난 발생이 이루어지는지 알아보기 위해 생존율, 성비, 비만도, 생식소 발달빈도, 생식소지수, 수정률, 부화율 및 D형 유생까지의 발생소요시간을 조사하였다. 생존율은 대조구에 비해 가온구에서 낮았으며, 성비는 암컷의 비율이 높았다. 비만도는 대조구와 가온구가 유의한 차이를 보이는 가운데 수온 $17^{\circ}C$ 이상부터 증가폭이 높게 나타났다. 생식소발달빈도는 암 수 모두 대조구의 경우 발달이 느렸으며, 가온구는 수온 $20^{\circ}C$인 사육 21일부터 28일 사이에 성숙기에 도달한 개체들이 80%이상 관찰되었다. 생식소지수는 대조구에 비해 수온이 높을수록 증가하는 경향을 보였다. 새꼬막의 수정률은 $82.17{\pm}3.55%$ 였으며, 부화율은 $63.57{\pm}2.36%$로 나타났다. D형 유생의 발생소요시간은 약 15시간으로 나타났다.

• 한국양식학회지
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• 제16권4호
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• pp.245-251
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• 2003

2000년 1월부터 12월까지 남해안 한산만 해역에서 채집한 홍합의 생식소 발달과 생식주기에 관하여 조직학적 방법을 이용하여 조사하였다. 홍합은 자웅이체이며, 생식소는 암 수 모두 다수의 배우자형성소낭으로 이루어져 있었다. 생식소지수(GI)는 2월(3.40)에 가장 높았으며, 8월(1.18)에 가장 낮았다. 비만도(CI)는 생식소지수(GI)와 유사하게 변화하였다. 홍합의 주 산란기는 2∼3월이며, 생식주기는 휴지기(8∼11월), 분열증식기(11∼12월), 성장기(12∼1월), 성숙기(1∼2월), 부분방출기(2∼4월), 완전방출 및 퇴화흡수기(4∼7월)로 구분할 수 있었다. 성비(암:수)는 1:0.96으로 조사되었다.

• 한국패류학회지
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• 제23권2호
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• pp.199-208
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• 2007

2006년 1월부터 12월까지 전북 부안군 격포리에서 월별로 채집된 홍합, Mytilus coruscus를 대상으로 생식주기를 조사하였다. 홍합은 자웅이체이며, 난소는 수많은 난소소낭으로 이루어 져 있으며, 정소는 다수의 정소소낭으로 구성되어 있다. 생식소지수 (GI) 와 생식소중량지수 (GSI) 의 월별 변화는 2월에 최고값에 도달한 이후, 4월까지 점차 감소하였으며 GI 값과 GSI 값의 월별 변화는 서로 유사한 경향을 보였다. 비만도지수 (CI) 의 월별 변화는 생식소지수와 생식소중량지수의 변화양상과 유사한 경향을 나타내었다. 따라서 이들 세 가지 지수로부터 홍합의 산란기는 2-4월로 판단된다. 조직학적 조사에 의한 홍합의 산란기는 2-4월이었으며, 주 산란기는 2-3월이었다. 생식주기는 초기활성기 (11-1월), 후기활성기 (11-2월), 완숙기 (12-4월), 부분산란기 (2-4월), 퇴화기 (4-10월), 휴지기 (6-12월) 로 구분되었다. 각고에 따라 홍합의 군성숙도를 조사한 결과, 각고 40.1-50.0 mm인 개체들은 군성숙도 50% 이상 (암컷 71.4%, 수컷 78.9%) 이었고, 각고 50.1 mm 이상인 개체들은 군성숙도 100%이었다. 12개월간 채집한 총 개체들의 성비를 검증한 결과, 암수 성비는 1:1로 유의한 차이를 보이지 않았다 $(x^2\;=\;0.63,\;p\;>\;0.05)$.

• 한국환경과학회지
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• 제22권1호
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• pp.37-45
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• 2013

The monthly variations of blood characteristics and RNA/DNA of black sea bream, Acanthopagrus schlegeli, habituated in Geojae costal area were analysed to determine health condition of natural stocks in terms of gonad maturation and spawning season from March 2010 to February 2011. Spawning season determinated by gonadosomatic index is from June to August. RNA/DNA ratio of black sea bream muscle was strongly correlated with spawning season. During the gonad maturation RNA/DNA ratio in dorsal muscle tissue was decreased contrast to rapid increase during spawning season. Blood composition factors increased in terms of gonad maturation are aspartate aminotransferase, cholesterol, triglyceride, total protein, glucose, globulin, alkaline phosphatase and inorganic phosphate. Other blood factors increased during spawning season are alanine aminotransferase, blood urea nitrogen, uric acid and lactate dehydrogenase.

• 한국발생생물학회지:발생과생식
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• 제21권2호
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• pp.223-228
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• 2017

This study investigated the effect of different photoperiods (14L: 10D, 12L:12D and 10L:14D) on the gonadal development and GtH mRNA expression in the pituitary of damselfish. The results showed that gonadosomatic index (GSI) was significantly lower in shot photoperiod (10L:14D), in comparison with other photoperiodic group during the spawning season. After 60 days treatment, histological analysis of gonad tissue showed that the gonad of 10L:14D and 12L: 12D treatment groups were resting phase with spermatogonia and perinucleolus stage oocytes but the gonad of 14L:10D treatment group was still ripe phase with spermatozoa and mature stage oocyte. The $FSH{\beta}$ and $LH{\beta}$ mRNA expression in pituitary drastically decreased shot photoperiod treatment from July (spawning period). These results suggest that photoperiod is considered to be the most effective environmental factor in controlling the reproductive cycle of damselfish.

• 한국발생생물학회지:발생과생식
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• 제24권3호
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• pp.225-230
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• 2020

This study reports the presence of mature and bi-sexual phase gonads in red spotted grouper, Epinephelus akaara after less than a year of cultivation in a commercial indoor tank and a net cage. In December 2018, juveniles were placed in an indoor tank and cultured for five months. In June 2019, the fish were transferred to a net cage and cultured until September. The rearing temperatures ranged from 19.86℃-24.65℃ in the indoor tank and 21.86℃-27.65℃ in the net cage. During the net cage culture period, specimens were randomly selected for histological gonad examination. The highest gonadosomatic index (GSI) value was measured in July (3.38±2.53), and dramatically decreased in August (0.44±0.21) and September (0.42±0.30). In July, some mature fish showed signs of vitellogenic stage oocyte development (vitellogenic and oil droplet stage oocytes), but immature fish were in an early developmental stage containing peri-nucleolus stage (PNS) oocytes. Bi-sexual phase gonads containing spermatocytes and spermatids were observed in the lumen and several PNS oocytes. By August and September, most specimens showed early-stage ovary development. However, mature testis (in August) and bi-sexual phase gonads (in September) were also observed. These results provide evidence for early puberty and hermaphroditism in the red spotted grouper.

• 한국패류학회지
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• 제23권2호
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• pp.165-172
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• 2007

우리나라 남해안 강진만에서 2006년 5월부터 2007년 4월까지 채집된 개조개의 생식소 발달과 생식주기를 조직학적으로 조사하였다. 개조개는 자웅이체로 난소는 수많은 난소소낭 (oogenic follicle) 으로 이루어져 있으며, 정소는 다수의 정소 소낭 (acinus) 으로 구성되어 있다. 생식소지수는 4월에 최고값을 나타내었고, 그 후 감소되어 7월에 최저값를 나타내었다. 비만도지수는 6월에 최고값을 보였고, 그 후 감소되어 11월에 최저값을 보였다. 개조개의 생식주기는 회복 및 휴지기 (6-12월), 초기활성기 (1-4월), 후기활성기 (2-7월), 완숙기 (3-10월), 방출기 (4-10월)로 구분되었다. 강진만에서 개조개의 주산란기는 7-9월이었다. 암, 수 성비는 1:1로 유의한 차를 보이지 않았다.