• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2002.10a
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• pp.282-283
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• 2002

Corbicula (Corbiculina) papyracea (Heude) is fresh water clam which lives on the sands and muds, its size was about 3~25 mm with yellow gray color. Shell width of the clam is thin and smooth and growth lines are marvelous and inside of shell colored pink or pink with red. And the clam reproduces itself through virgin generation (Park et al., 1989), ovoviviparous (Kwon et al., 2001) method. There are reports about Corbicula by Kim and Yoo (2000), Kwon et al. (1987), and Lee et al. (1985) but there aren't many report about C. (C.) papyracea. The aim of this work is to present the dynamics of D.(C.) papyracea from Chungpyeong.

• The Korean Journal of Ecology
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• v.28 no.2
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• pp.63-67
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• 2005

The eleven local samples of six species including Corbicula leana examined in this study were collected from the Nam River and the Nakdong River in Korea. Buzas's new formula was used to evaluate the ecological biodiversity among eleven populations and six species. In addition, enzyme electrophoresis was used to genetic diversity within and among populations of C. leana. The upper populations of the river have fewer species than the middle and low populations of this river. The genetic diversity trends to increase from the source of the main river to the mouth. It suggests that the population of downstream might be expanded toward upstream.

• Development and Reproduction
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• v.13 no.2
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• pp.115-122
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• 2009

Spermatogenesis and ultrastructural characteristics of sperm of brackish water diploid Corbicula japonica were investigated by electron microscope observations. Based on the cytological studies, the spermatozoon of this species (brackish water diploid) C japonica is approximately 55 ${\mu}m$ in length. The sperm head (about 12 ${\mu}m$ long) is elongated and tapers with a slight curve. Sperm nucleus is about 7.90 ${\mu}m$ long, and the acrosome is about 2.70 ${\mu}m$ long: The morphologies of the sperm nucleus type and the acrosome shape of this species are a long arrow-like type and long cone-like shape, respectively. The sperm head of this species (external fertilization, dioecious and oviparous species) is partially modified from that of the primitive type, as seen in triploid Corbicula species (internal fertilization, hermaphrodite and ovoviparous species), reported by some authors. However, this species produces uniflagellate spermatozoa, unlike freshwater triploid hermaphroditic clams being possessed of partially modified biflagellate spermatozoa. Diploid C japonica is similar to those of other bivalves being possessed of a short midpiece containing four mitochondria surrounding the centrioles. The axoneme of the sperm tail flagellum consists of nine pairs of microtubules at the periphery and a pair at the center. The axoneme of the sperm tail shows a 9+2 structure, and from uniflagellate sperm cross sectioned, in particular, wing-like axonernal lateral fins are observed, as seen in external fertilization fishes.

• The Korean Journal of Malacology
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• v.23 no.1
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• pp.39-49
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• 2007

We investigated to understand the differences in the karyotypes and the reproductive characteristics between the diploid clam, Corbicula japonica in the brackish water and the triploid clam, C. fluminea in the freshwater. The number of chromosomes of the diploid C. japonica were 38, which can be grouped into 19 pairs of two homologues. These can be divided into 11 pairs of telocentric, 4 pairs of subtelocentric, 3 pairs of submetacentric and one pair of metacentric chromosomes. C. japonica is oviparous and dioecious. The clam has two pairs of gills, with the inner and outer-demibranchs, however, they do not act mainly as marsupia. External fertilization occurs in the brackish water. The triploid marsh clam, C. fluminea has 54 chromosomes, which can be grouped into 18 sets of three homologues. These 18 sets can be divided into one metacentric group, five submetacentric groups and 12 subtelo- or telocentric groups. C. fluminea is ovoviviparous and functional hermaphrodite. The triploid condition may be closely related to hermaphroditism. This species has the inner-demibranchs acting mainly as marsupia. The depletion of ripe eggs occurred in the inner-demibranchs of the gill during the incubatory periods, and ripe eggs produced in the hermaphroditic follicles in the gonad during the non-incubatory periods. The gonad developmental stages of two marsh clams (C. japonica and C. fluminea) can be divided into five stages: early active stage, late active stage, ripe stage, partially spawned stages, and spent/inactive stage.

• The Korean Journal of Malacology
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• v.14 no.2
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• pp.161-166
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• 1998

Mollusks were collected with Ponar grab from seven stations in lower part of Han river, Korea from June 1995 through May 1996. Basket sampler with artificial substrate was also employed to collect the adhesive mollusks. In addition to above mentioned sampling stations, Bam islet was surveyed. A total of species, Corbicula fluminea, Anodonta woodiana, Unio douglasiae, Limnoperna fortunei, corbicula fenouilliana and Physa acuta, were collected in lower part of Han river. Author reviewed the literatures on the ecological survey of molluscan fauna in Han river.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.05a
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• pp.518-519
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• 2000

재첩류는 담수와 기수역에 넓게 분포하는 식용 패류로서, 일본재첩은 우리 나라 기수역에서 다량 서식하는 유용패류이다. 일본재첩에 관한 연구는 생식생태학적연구 (조비,1941: 조등, 1997; 조 등,1998)와 생장(宇藤, 1981)이 있을 뿐이다. 그러나, 국내에 서식하는 일본재첩, Corbicula japonica의 생식생태에 관한 연구가 매우 미진할 뿐만 아니라, 이들의 생식생태에 관한 계수학적 정량분석조사는 되어있지 않다. 따라서, 본 연구는 일본재첩의 생식생물학적연구의 일환으로 생식소의 구조, 생식주기, 생식소지수의 월별변화, 생식세포발달과정, 성비를 조사하였고 계수학적 정량분석을 실시하였다. (중략)

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.10a
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• pp.349-350
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• 2001

엷은재첩 Corbicula papyracea (Heude)은 이치아강 (Heterodonta) 백합목 (Veneroida) 재첩과(Corbiculidae)의 패류로 모래가 많은 진흙 바닥에 서식한다. 소형종으로 옅은 황갈색 바탕에 녹색을 띠고 있다 각폭이 엷으며 성장맥이 나늘고 폭이 좁아 조밀하다. 패각의 내면은 보라색 또는 진한 보라색을 띠고 있다. 개체수가 많지 않다. 난태생을 하며, 전국적으로 분포한다 (권오길 외). (중략)

• Journal of Aquaculture
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• v.15 no.1
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• pp.23-29
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• 2002

To develop techniques for the production of artificial seedling of Corbicula japonica, protocols for induction of spawning and larval development were developed. During the assumed spawning period of August to mid-September, attempts were first made to induce spawning by gonadal incision and UV-irradiation but all in vain. At the end of August, elevated thermal induction evoked 90 % positive response in animals maintained at $3\textperthousand$ salinity. Immersion in (1/1000~3/1000 N) ammonium hydroxide ($NH_4$OH) also induced spawning in 15~45%) of the treated animals at $3\textperthousand$ salinity. Fertilized eggs measured 86$\mum. At 23.0~24.5$^{\circ}C$, the fertilized egos developed into 4-cell stage embryos within 2 hours, trochophores 15 hours, D-shaped larvae 2 days, umbo 9 days and fully grown veligers, ready to infiltrate into the sediment, within 16 days.

• The Korean Journal of Malacology
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• v.21 no.1
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• pp.57-64
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• 2005

Samples of Corbicula japonica Prime of Jujin estuary in Gochang were collected from July 2000 to September 2001. Age of C. japonica was determined from the rings on the shell. The relationship between shell length and ring radius in each ring group was expressed as a regression line. Therefore, there is a correspondence in each ring formation. Based on the monthly variation of the marginal index (MI') of the shell, it is assumed that the ring of this species was formed once a year during the period of February and March. The relationship between shell length (SL; mm) and total weight (TW; g) was expressed by the following equation: TW = 1.0942 ${\times}10^{-4}SL^{3.3217}$ ($r^2$ = 0.9905). Shell length (SL) and shell height (SH; mm) was highly correlated with shell height as the following equation: SH = 0.9174 SL - 0.9935 ($r^2$ = 0.9885). The shell length (SL) - shell width (SW) relation was also expressed by the following equation; SW = 0.5925 SL - 1.1706 ($r^2$ = 0.9726). Growth curves for shell length and total weight fitted to the von Bertalanffy's growth curve were expressed as: $$SL_t = 46.4861[1-e^{-0.3383(t+0.0958)}]$$, $$TW_t = 34.54[1-e^{-0.3383(t+0.0958)}]^3.3217$$.

• Journal of the korean society of oceanography
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• v.35 no.1
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• pp.56-64
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• 2000

The importance of terrestrial organic matter as a food source for a brackish water clam Corbicula japonica was evaluated using stable carbon isotope ratios (${\delta}^{13}$C) in its tissues and potential food resources in an estuarine system of Youngil Bay, Korea. Suspended particulate organic matter (POM) had distinct ${\delta}^{13}$C values from riverine (-31.8 to -27.2%$_o$) to marine waters (-21.0 to -16.6%$_o$). Estuarine macroalgae had a wide ${\delta}^{13}$C range of -22.8 to -15.0%$_o$. The ${\delta}^{13}$C values of riverine POM were more negative than that of riverine phytoplankton (-26.5 to -24.2%$_o$) but similar to that of freshmarsh plant species (-29.1 to -27.5%$_o$ for Phragmites communis and -28.5 to -27.0%$_o$ for Salix gracilistyla), These ${\delta}^{13}$C values suggest that the POM transported by the Hyungsan River is predominantly of terrestrial origin rather than riverine autochthonous sources. The ${\delta}^{13}$C values of Corbicula japonica tissues (-28.7 to -27.2%$_o$) were most similar to values for riverine POM and freshmarsh plants. There was no significant difference in the isotopic composition of the clam individuals. The results indicate a predominant contribution of organic carbon derived from terrestrial and fresmarsh plant detritus to the diet of Corbicula japonica. Our results also confirm previous suggestion that terrestrial organic matter can be incorporated into estuarine food webs although its role is confined to the upper estuarine reaches.