• 한국어류학회지
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• 제12권3호
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• pp.192-202
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• 2000

주둥치의 암 수 성비는 1.81 : 1로 암컷의 비율이 높게 나타났다. 난모세포 발달양식은 난군동기발달형에 속하며, 정소 조직상은 정원세포 국재형에 속한다. 암 수 모두 첫 번째 군 성숙에 도달하는 크기는 전장 7.5 cm로 조사되었다. 암컷의 생식소중량지수(GSI)는 7월에 12.83으로 가장 높았고, 9월에는 1.08로 가장 낮았다. 수컷의 GSI는 6월에 19.0으로 가장 높았고, 10월에 0.24로 가장 낮았다. 암컷의 간중량지수(HSI)는 GSI와 같은 경향의 변화를 보였다. 가슴반점지수(TSI)는 생식소의 성숙 및 완숙시기인 5월부터 7월 사이에는 낮은 값을 보였다. 암컷의 생식주기는 성장기 (3~5월), 성숙기(5~6월), 완숙 및 산란기 (6~8월), 회복기 (8~11월) 그리고 휴지기 (11~3월)로 구분할 수 있었다. 수컷의 생식주기는 분열증식 및 성장기 (1~4월), 성숙기 (4~5월), 완숙 및 방정기(6~8월), 회복기 (8~10월) 그리고 휴지기(10~12월)로 구분할 수 있었다.

• 한국패류학회지
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• 제29권4호
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• pp.313-323
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• 2013

Gonad development, the reproductive cycle, first sexual maturty and size at 50% of group sexual maturity (the biological minimum size) of Gomphina (Macridiscus) veneriformis were investigated for clams collected from the coastal waters of Donghae City, the East Sea of Korea by histological, and morphometric analysis. Monthly variations of the gonad index showed a pattern similar to that of the reproductive cycle. The reproductive cycle with the gonad developmental stages in female and male G. (M.) veneriformis can be classified into five successive stages: early active stage (December to March), late active stage (March to June), ripe stage (June to July), partially spawned stage (June to August), and spent / inactive stage (September to December). The spawning period continued from June to August, with a peak between July and August when the seawater temperature exceeds $20^{\circ}C$. The percentages of first sexual maturities of female and male clams ranging from 25.1 to 30.0 mm were 56.3% in females and 61.1% in males, and for clams over 30.1 mm shell length, it was 100%. Shell lengths at 50% of group sexual maturity (biological minimum size, $RM_{50}$) were 27.71 mm in females and 26.31 mm in males. Because harvesting clams < 26.31 mm in shell length could potentially cause a drastic reduction in recruitment, a measure indicating a prohibitory fishing size should be taken for adequate fisheries management.

• 한국수산과학회지
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• 제42권1호
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• pp.41-47
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• 2009

The seasonal reproductive cycle of Gomphina melanaegis collected in the coastal area of Jumunjin, between April 2006 and March 2007, was analyzed. Maturation cycle parameters such as the gonad index (GI), ovarian egg diameter, frequency of developmental stages, protein content, and RNA/DNA variation in the gonads were analyzed monthly for the 40 samples. According to the indices from histological sections, the frequency of gonad developmental stages, and the oocyte diameter, this clam has a long-term partial spawning pattern from March to October. However, GI and nucleic acid values showed that the mature stage is from March to July and that the main spawning season is August. The peak RNA and DNA contents were good indicators of sexual maturation in females and males, respectively. The variation in protein content corresponded with the RNA/DNA ratios.

• 한국발생생물학회지:발생과생식
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• 제22권2호
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• pp.175-182
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• 2018

In order to examine the effects of four different light spectra (white, red, green, and blue) on the oocyte maturation, the change of reproductive parameters, via brain-pituitary-gonad (BPG) axis in grass puffer, were investigated. After exposure four different light spectra for 7 weeks, the abundance of gonadotropin-releasing hormone (GnRH) mRNA which is a type of seabream (sbGnRH) and two different subunit of gonadotropin hormones mRNAs, follicle-stimulating hormone ($fsh{\beta}$) mRNA and luteinizing hormone ($lh{\beta}$) mRNA, were analyzed in the brain and pituitary. Histological analysis showed that the mature oocyte ratio in the green spectrum was higher than other light spectra-exposed groups. Gonadosomatic index (GSI) and oocyte developmental stage were also investigated in the gonad based on histological observations. GSI value with the presence of yolk stage oocytes was significantly increased in the green spectrum-exposed group when compared to that of the other light-exposed groups (white, red, and blue) (p<0.05). The abundances of sbGnRH mRNA and $fsh{\beta}$ mRNA in the green spectrum-exposed group were also significant higher than those of the other light spectra-exposed groups (p<0.05). These results indicate that the maturation of oocyte in grass puffer can be accelerated by exposure to the spectrum of green. To better understand the molecular mechanism for the maturation of oocyte in grass puffer, further study examining the relationship between oocyte development and its related genes is required.

• 한국양식학회지
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• 제21권4호
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• pp.252-258
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• 2008

전라남도 여수시 소라면 여자만에서 2007년 3월부터 2008년 2월까지 채집된 새꼬막 Scapharca subcrenata의 생식소 발달과 생식주기를 조직학적으로 조사하였다. 새꼬막은 자웅이체로 난소는 많은 난소 소낭(oogenic follicle)으로 이루어져 있으며, 정소도 많은 정소 소낭(acinus)으로 구성되어 있다. 생식소지수(GI)는 6월에 연중 최고 값을 나타내었고, 그 후 감소하여 7월에 최저 값를 나타내었다. 비만도지수(CI)는 4월에 연중 최고 값을 보였고, 그 후 감소하여 7월에 최저 값을 보였다. 새꼬막의 생식주기는 초기 활성기($1{\sim}4$월), 후기 활성기($3{\sim}6$월), 완숙기($5{\sim}8$월), 방출기($7{\sim}9$월) 그리고 회복 및 휴지기($9{\sim}3$월)의 연속적인 발달 단계로 구분되었으며, 주 산란기는 $7{\sim}8$월로 조사되었다. 암, 수 성비는 1:1로 유의한 차를 보이지 않았다.

• 한국패류학회지
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• 제16권1_2호
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• pp.35-41
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• 2000

1999년 4월부터 2000년 3월까지 서해 금강 하구인 내 초도에 서식하고 있는 가무락조개를 대상으로 자원증식 및 적정 관리를 위해 조직학적 방법에 의해 생식소지수, 생식 소발단단계에 따른 생식주기, 군성숙도를 조사하였다. 가무락조개는 자웅이체로서 난생이다. 가무락조개의 생식주기는 초기활성기(2-4월), 후기활성기(3-6월), 완숙기(4-8월), 부분산란기(7-10월초), 퇴화 및 비활성기(9-2월)의 연속적인 5단계로 구분할 수 있었다. 가무락조개의 산란기는 수온과 밀접한 관계를 가지며 수온이 24$^{\circ}C$이상인 7월부터 산란하기 시작하여 9월 중순까지로 산란성기는 7, 8월이었다. 고창산 가무락조개의 군성숙도는 각장 26.0-30.0 mm 사이에서 암, 수 공히 50% 이상이 재생산에 가담하였고, 각장 41.0 mm 이상에서는 100%가 산란에 참여하고 있다. 전 개체의 50%가 재생산에 가담하기 시작하는 개체들의 연령은 만 2세로 추정된다.

• 한국패류학회지
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• 제20권1호
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• pp.65-73
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• 2004

Gametogenesis, changes of gonad bulk index (GBI), monthly variation in oocyte diameter, reproductive cycle and spawning with lunar cycle of the top shell, Trochus niloticus were investigated by histological examination. The specimens were sampled in the coastal waters of Chuuk Island, Micronesia, form November 1999 to September 2000. T. niloticus is a gonochorism, and the female and male were present in an approximately 1:1 ratio (p > 0.05). The ovary contained with the oocyte of yolk stage, the testis composed of the spermatid and spermatozoa at around the year. Monthly GBI were higher at February, March, April and June than the other months. Major spawning occurred between April and May, and June and July but the individuals of partially spawning were presented throughout the year. GBI with lunar cycle were higher at the full moon than the other lunar phase. These results suggest that the spawning occurred between the full moon and last quarter moon.

• Fisheries and Aquatic Sciences
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• 제9권1호
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• pp.7-13
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• 2006

Using biochemical methods, we determined the potential of local female shrimp populations as breeding stock to select the best adult prawns for improving larval production. As condition indexes, we selected total RNA, DNA, their ratio, and trypsin activity. The DNA content in the pleopods of each local population was similar, i.e., between $0.90{\pm}0.06\;and\;1.02{\pm}0.04(SE){\mu}g/mg$. In comparison, the RNA contents differed markedly between $2.00{\pm}0.09$ and $0.96{\pm}0.08\;{\mu}g/mg$. Therefore, the RNA/DNA (R/D) ratio in the pleopod could be used as a condition index because it represents a biochemical characteristic of the population. The mean pleopodal R/D ratio of the Goheung population was the highest at $2.52{\pm}0.19$, which indicated the best condition. Trypsin activity was influenced little by shrimp condition and more by the amount of food ingested. The gonadosomatic index (GSI) and R/D ratio in the gonads provided offsetting information about the instantaneous gonad maturity. The Goheung population had the highest instantaneous GSI, despite some spawning. Based on the condition indexes and time of gonad maturation, the Goheung shrimp population is suitable for use as breeding stock.

• 한국양식학회지
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• 제22권1호
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• pp.34-41
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• 2009

전라남도 여수시 소라면 여자만에서 2002년 1월부터 12월까지 채집된 꼬막의 생식소 발달과 생식주기를 조직학적으로 조사하였다. 꼬막은 자웅이체로 난소는 많은 난소 소낭(oogenic follicle)으로 이루어져 있으며, 정소도 많은 정소 소낭(acinus)으로 구성되어 있다. 생식소지수(GI)는 6월에 연중 최고 값을 나타내었고, 그 후 감소하여 8월에 최저 값을 나타내었다. 비만도지수(CI)는 7월에 연중 치고 값을 보였고, 그 후 감소하여 9월에 최저를 나타냈다. 꼬막의 생식주기는 초기 활성기($3{\sim}5$월), 후기 활성기($4{\sim}6$월), 완숙기($5{\sim}7$월), 방출기($7{\sim}8$월) 그리고 회복 및 휴지기($9{\sim}3$월)의 연속적인 발달 단계로 구분되었으며, 주 산란기는 $7{\sim}8$월로 조사되었다. 암 수 성비는 1:1로 유의한 차를 보이지 않았다.

• Fisheries and Aquatic Sciences
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• 제1권1호
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• pp.82-93
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• 1998

Monthly changes of the gonad follicle index (GFI), reproductive cycle, egg-diameter composition, first sexual maturity of the Pacific oyster, Crassostrea gigas, were studied based on the samples which have been collected from the intertidal zone of Poryong west coast of Korea, from January to December, 1996. C. gigas, is dioecious, while a few individuals are alternatively hermaphroditic. Monthly variation of gonad follicle index (GFI) used for determination of spawning period, coincided with the reproductive cycle. GFI increased from April when seawater temperatures gradually increased and reached the maximum in May. And then, GFI sharply decreased from June to September due to spawning. Reproductive cycle of this species can be divided into five successive stages: in females, early active stage (March to April), late active stage (April to May), ripe stage (May to August), partially spawned stage (June to September) and spent/inactive stage (September to February); in males, early active stage (February to March), late active stage (April to May), ripe stage (May to September), partially spawned stage (June to September) and spent/ inactive stage (September to February). The diameter of fully mature eggs are approximately 50um. Spawning occurred from June to September, and two spawning peaks were observed in June and August when the seawater temperature was above $20^{\circ}C$. Percentages of the first sexual maturity of males of 20.1-25.0 mm in shell height were over $50\%$, while those of females of 25.1-30.0 mm in shell height were over $50\%$. All the males of > 30.1 mm and all the females of ^gt; 35.1 mm completed their first sexual maturity. The results suggest that C. gigas has a protandry phenomenon. Sex ratios of 919 oysters observed were 453 females $(49.29\%)$, 429 males $(46.68\%)$, 16 hermaphrodites $(1.74\%)$, and 21 indeterminate individuals $(2.29\%)$. In age class I, sex ratio of males were $64.00\%$, thus, a higher percentage than that of females. It was noted that $64.00\%$ of the young males (age class I) were more functional than females in age class I, but 2-3 year-old oysters showed higher percentage of females. Percentages of hemaphrodites in 2-3 year classes were relatively higher than those in other year classes. Histological pattern of hermaphrodites can be divided into two types: Type I (hermaphrodite having a number of newly formed developing oocytes on the oogenic tissues within a degenerating spermatogenic follicle after discharge of numerous spermatozoa) and Type II (hermaphrodite having two separate follicles in the same gonad).