• Animal cells and systems
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• 제16권1호
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• pp.77-84
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• 2012

The objective of the study was to investigate if reproductive characteristics of $Pandalus$ $eous$ affect the depth distribution in the East Sea of Korea. $P.$ $eous$ was found at depths of 500-900 m in the East Sea of Korea, with the highest percentage occurrence (34%) at 500 m. A negative correlation was observed between the number of individuals and the depth. The overall sex ratio also turned out to be significantly correlated with depth. On average, the larger individuals (bigger than 26.37 cm), which included transitional, female, and ovigerous females, were mostly distributed at 700 m depth. The percentage of males increased by depth and ovigerous females were mainly distributed in the shallow water (300 m) during winter. Ovigerous females were not found at 900 m, which is the deepest depth range in this study. The percentage of transitional individuals was greatest at 500 m and decreased gradually with depth. All ovigerous female individuals were of the spent ovarian stage in winter. Female numbers in the ripe ovarian stage increased with depth and immature females rarely appeared. The gonadosomatic indices of the nonovigerous females and ovigerous females were highest at 700 m in depth. The mean egg size of $P.$ $eous$ was $0.83{\pm}0.11mm^3$ in the non-eyed stage and $0.93{\pm}0.17mm^3$ in the eyed stage.

• 한국수산과학회지
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• 제22권5호
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• pp.351-362
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• 1989

Ecology of Crangon affinis was studied in the Nakdong River Estuary fron June 1988 to May 1989. The growth rate of female was similar to that of male. Size differences, however, were apparent between female and male. Sex ratio varies with season. The major spawning season was from June 1988 to May 1989 except for November 1988. The number of eggs of the largest ovigerous female (35.55mm TL) was over 4,000, while that of the smallest ovigerous female (15.05mm TL) more than 120. The mean number of eggs was 1778. The size of winter eggs is larger than that of the summer eggs. The mean percentage of egg loss from brooding to hatching was $29.06\%$. The rate of egg loss decreases with increasing age. Major component of food organisms includes mysids and polycheates.

• 한국수산과학회지
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• 제57권1호
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• pp.60-68
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• 2024

The size distribution, maturation, and molting stages of the snow crab Chionoecetes opilio in the coastal sea of Gyeongbuk were investigated to understand its monthly and bathymetric occurrence patterns. C. opilio was collected from three depth strata (A1, 100-120 m; A2, 120-180 m; A3, 180-220 m) from May to November 2020. The average sex ratio was 0.8. The mean carapace width was largest in females in October, and in males in November. The occurrence rate of small immature crabs was the highest in A1. The ratio of ovigerous females at 75-80 mm was highest at A2 and A3. There was a significant difference in carapace width in females and depth in both sexes in September and October. The occurrence rate of immature crabs was the highest in A1, whereas that ovigerous and spawned females was higher in A2 and A3 than in A1. Very old-shelled females occurred highly in September and October. The occurrence rate of newly shelled males was higher throughout the study period. This research indicated that the size distribution, maturation conditions, and molting stages of C. opilio varied with water depth strata in the coastal sea of Gyeongbuk, Korea.

• Animal Systematics, Evolution and Diversity
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• 제23권2호
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• pp.205-208
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• 2007

The first zoeal characters of plagusiine crab Plagusia dentipes De Haan, 1835, belonging to the family Grapsidae, is described and illustrated in detail based on laboratory-hatched material from an ovigerous female collected from Bomok, Seogwipo in the Jejudo Island. Morphological comparison is made with previous description of Plagusia dentipes from Japan. The first zoea of Plagusia dentipes can be readily distinguished from those of two species of Plagusia chabrus and Plagusia depressa by having 2 aesthetascs and 3 simple setae on the antennule, and 8 setae on the coxal endite of the maxilla.

• 한국수산과학회지
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• 제43권6호
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• pp.670-678
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• 2010

An ecological investigation was conducted in winter from November 2007 to February 2008, around Wangdol Reef in the East Sea to analyze the population structure and fecundity of Chinoecetes opilio. The sex ratio was 30.11:69.89% (female:male) in November, 62.03:37.97% in December, 37.59:62.41% in January and 14.69:85.31% in February. Regression equations indicated highly positive relationships between size and weight parameters (carapace length, width, total weight). During the sampling period ovigerous females were continuously collected. The percentage of ovigerous females was 96% in November, 90.57% in December 89.80% in January, and 88.46% in February. The average number of embryos was 64,800. The regression equation between carapace width and the number of embryos was y = 2.6805x - 0.9182 ($R^2$ = 0.7166). Embryo volume increased as embryo development proceeded. The mean size of an embryo was 0.72 mm. Embryo volume ranged from 0.42 to $0.84\;m^3$ during embryo developmental stages 1 to 3.

• 한국해양학회지
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• 제26권2호
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• pp.101-107
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• 1991

영산강 하구역에 분포하는 진주담치에 기생하는 요각류, Pseudomyicola spinosus 의 계절 변동을 조사했다. 본 종은 일년에 4세대를 영위하며 여름에 나타난 세대의 개 체수가 가장 많았다. 성비는 9월을 제외하고 6∼10월은 수컷이 1월을 제외한 11∼5월 은 암컷성체가 각각 우세하게 나타났다. 포란성체는 2월을 제외하고 연중 발견되었다. 포란성체가 많이 나타난 1개월 후에는 copeodid가 많이 출현하였다. copeodid는 1∼3 기는 전체의 약 4%에 불과하였으며, 이러한 결과는 copeodid 3기에 본격적인 감염이 이루어지고 있음을 시사하였다.

• 한국어류학회지
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• 제7권2호
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• pp.150-159
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• 1995

1992년 5월부터 1993년 8월까지 부산 수영만 인근해역에서 채집된 망상어, Ditrema temmincki를 대상으로 조직학적 방법에 의해 생식주기와 군성숙도를 조사하였다. 조사된 결과는 다음과 같다. 본종의 군성숙도는 수컷은 체장 13.5cm, 암컷은 체장 12.5cm로 조사되었다. 생식소중량지수는 수컷은 10월, 암컷은 6월에 연중 가장 높은 값을 나타냈다. 정소의 내부조직상은 곡정세관형이며, 난소는 5∼6장의 난소습곡으로 이루어져 있는데, 곡정세관상피와 난소습곡상피에서 각각 정원세포와 난원세포가 유래한다. 생식주기는 수컷은 성장기(5∼8월), 성숙기(9∼10월), 교미기 (11∼12월), 퇴화 및 휴지기 (1∼4월)로 나눌 수 있으며, 암컷은 성장기 (9∼10월), 교미 및 성숙기 (11∼12월), 임신기 (1∼6월), 휴지기 (7∼8월)로 나눌 수 있다. 간중량지수는 암수 모두 4월에 최고치를 보여, 수컷에서는 생식소중량지수의 월변화와 역상관 관계를 보이고, 암컷에서는 정상관 관계를 보였다.

• 생명과학회지
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• 제9권5호
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• pp.518-524
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• 1999

Timing of oviposition, nuclear maturation of oocytes, egg-sperm contact and brooding were observed in the giant fresh-water prawn Macrobrachium rosenbergii reared in the laboratory. When a pre-spawning molted female was transferred to the male, the female oviposited commonly at 5 to 10 hr after mating. The first polar body were extruded within 2-3 min after spawning. The egg chromosome progressed to release second polar body by 30 min and mitotic nuclear division occurred in 8 hr after spawning. Thumbtack-shaped spermatozoa were seen peneterating egg membrane with their spike directed forward. Transformation of spermatozoa and fertilization membrane could not be observed by light microscopy. The elapsed hours from oviposition to the end of brooding wee taken in 5-7 hr. Brood size for female 9 cm and 18 cm in body length was estimated to be 10,000~15,000 and 100,000 eggs, respectively and is proportional to the total length of the berried females. The ovigerous females reared at chlorinity of 2.21~4.25$\textperthousand$Cl. showed a normal egg development up to hatching.

• Animal Systematics, Evolution and Diversity
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• 제23권1호
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• pp.69-74
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• 2007

First zoea of cyclograpsinine crab Chasmagnathus convexus (De Haan, 1835) belonging to the family Varunidae, is described and illustrated in detail based on laboratory-hatched material from an ovigerous female collected in Seumjingang river mouth, southern Korea. Morphological comparison is made with previous description of C. convexus from Japan, The first zoea of C. convexus can be readily distinguished from those of six species of Cyclograpsus intermedius Ortmann, 1894, Helicana japonica (K. Sakai and Yatsuzuka, 1980), Helicana wuana (Rathbun, 1931), Helice tientsinensis Rathbun, 1931, Helice tridens (De Man, 1835), and Pseudohelice quadrata (Dana, 1851), the other known cyclograpsinine species in Korea by having the lateral carapace spine, a pair of dorsolateral processes on the fourth abdominal somite, the exopod of antenna with three setae, and the exopod of antenna as being 24.7% length to the protopod.

• 한국해양학회지
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• 제30권2호
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• pp.138-146
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• 1995

본 연구는 강화도 연안 새우류(Decapoda, Macrura) 군집의 우점종인 돛대 기새우 (Leptochela gracilis (STIMPSON, 1860))의 성장 양상을 조사하기 위해 실시되었다. 시료는 1개의 동일한 정점에서 낭장망을 이용하여 채집하였으며 1993년 4월부터 1994 년 1월까지 8월을 제외한 월별 채집을 하였다. 돛대 기새우의 포란 개체는 4월에서 9 월까지 출현하였는데 5월에서 7월의 포란률이 70% 이상나타나 포란성기로 여겨진다. 또한 성비는 4월을 제외한 조사 전월에 걸쳐 암컷이 우세하였으며 포란기와 비포란기 사이에 유의한 차이를 보이지 않았다(p>0.05). 돛대 기새우 개체군은 장기세대와 단기 세대의 두 형태의 세대로 나눌 수 있었고 장기세대의 수명은 1년에서 1년 3개월 정도 로 추측된다. 단기세대의 경우는 9월 포란군에 의해 산란되어 12월이후 감소하는데, 이들이 환경 요인들의 악화로 사망하는 것인지, 월동이후 성장률의 차이에 의해 장기 세대 병합되는 것인지는 밝힐 수 없었다. 장기세대를 Von Bertalanffy 성장식과 계절 변동을 고려한 Pauly and Gaschutz 성장식에 적용시켜본 결과 Pauly and Gaschutz 성 장식이 더 적합한 것으로 나타났다.