• The Korean Journal of Malacology
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• v.26 no.4
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• pp.255-260
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• 2010

This study was conducted to investigate protocol standardization for spermatozoa cryopreservation of the Scapharca broughtonii (Schrenck). Among the freezing rates, freezing at a height of 2 cm above liquid nitrogen surface for 5 minute gave higher activity and survival rate. Among the various diluents, Ringer's solution was the best for S. broughtonii sperm cryopreservation. The suitability of cryoprotectants dimethylsulfoxide (DMSO), dimethylacetamide (DMA), glycerol and methanol were tested against three freezing rates. DMSO gave significantly higher activity and survival rates than others.

• The Korean Journal of Malacology
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• v.26 no.2
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• pp.145-149
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• 2010

The effects of diluents composition on cold storage for Scapharca broughtonii (Schrenck) sperm were examined in the percentage of sperm activity and survival rate. Various diluents of glucose solutions (10 mM Hepes-pH 7.8), 600 mM NaCl, stein solution, Ringer's solution (230 mM NaCl, 8 mM KCl, 2 mM $CaCl_2$, 3.7 mM $MgCl_2$, 0.2 mM $NaHCO_3$, 10 mM Hepes-pH 7.8), 20%, 25% ASW (NaCl 2.7 g + KCl 0.07 g + $CaCl_2$ 0.12 g + $MgCl_2$ 0.46 g + $NaHCO_3$ 0.05 g + distilled water 100 ml) were used to store th sperm at $4^{\circ}C$. The storage effect was evaluated using sperm activity and survival rate. Ringer's solution was found to be better diluents which maintained high activity and survival rate of sperm for a storage period of 7 days. Optimal pH of diluents to store the sperm at $4^{\circ}C$ is 7.5.

• Proceedings of the Korean Aquaculture Society Conference
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• 2006.05a
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• pp.648-649
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• 2006

• Journal of Aquaculture
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• v.20 no.1
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• pp.31-40
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• 2007

To find out the effect of the spat planting time and environmental factors in the arkshell, Scapharca broughtonii (Schrenck), we investigated the growth, survival rate of arkshell and habitat characteristics in Gamak Bay, Yeoja Bay and Saryang Island. We planted artificial spats of arkshell in Gamak Bay and Yeoja Bay at November 2004, and also planted domestic and Chinese natural spats in Saryang Island at March 2005. We measured growth, survival rate of arkshell, physiochemical parameters of the water mass (water temperature, salinity, dissolved oxygen, nutrients and chlorophyll a) and characteristics of the sediment (oxygen penetration depth, oxygen microprofiles, ignition loss and chemical oxygen demand) by monthly. The cumulative survival ratio of arkshell in Gamak Bay was the highest at December, whereas the ratio of arkshell in Yeoja Bay was recorded as 0% at October. The monthly growth rates of arkshell length in Gamak Bay and Yeoja Bay were the highest in May and the growth rate of the Korean arkshell in Saryang Island was higher than Chinese ones significantly. The high mortality (> 65%) of the arkshell in Yeoja Bay during summer probably caused by high water temperature, inflow of low salinity water, and low dissolved oxygen concentration in sediment. The concentrations of nutrient and sediment COD were considered to play an important role in the monthly survival ratio of arkshell in Gamak Bay and Sarayng Island. We suggest that the growth and mortality of arkshell might be influenced to the planting time of spat and the habitat characteristics.

• The Korean Journal of Malacology
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• v.22 no.2
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• pp.175-182
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• 2006

Artificial induction of maturation by heating of the ark shell, Scapharca broughtonii (Schrenck) broodstock was investigated from 10th March to 21th May in 2004. Maturity at the fixed water temperature group of $23^{\circ}C$ was 60.5％, and it was the highest in maturity among experimental groups cultured for seven weeks. The proportions of organism surviving to start of S. broughtonii in the raised water temperature experimental groups (20 and $23^{\circ}C$) were over 90.5％, as similar to the control group (natural water temperature, 84.8％). But, the proportions of organism surviving to start of S. broughtonii in the fixed water temperature experimental groups (20, 23, and $26^{\circ}C$) were decreased with the increasing of the water temperature. In the fixed water temperature experimental groups of $26^{\circ}C$, the survival was 18.1％. Base on these results, the fixed water temperature of $20^{\circ}C$ (accumulated water temperature; $1,295^{\circ}C$) was the best condition for artificial induction of sexual maturation.

• Journal of Life Science
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• v.15 no.6 s.73
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• pp.879-883
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• 2005

This study was differentiated between Korea and China arkshells using PCR-aided RFLP method which could identify the variation for inter-and intra-species of arkshell (Scapharca broughtonii Schrenck) at the level of DNA. The DNA fragment patterns were compared after digesting gene of mitochondrial 16S rDNA with 8 kinds of restriction enzymes. A 720 bp DNA fragment corresponding to 16S rDNA gene was amplified by PCR with primers ArkF-3 and ArkR-3. PCR products were cut by restriction enzymes (Pvull, BamHI, Hinfl, HaeIII, EcoRI, RsaI, Ksp221, and BstX21), and RFLP pattern was studied. A unique 275 bp DNA band was observed in the samples from Dukyang, Gamak, Namhae, Jinhae, and Taean in Korea when treated by Hinfl, but Chinese arkshell did not show. Treatment of HaeIII could discriminate the sample of Namhae and Jinhae from Dukyang/Gamak/Taean, as well as Korean and Chinese arkshell based on a 700 bp. However, PuvII, BamHI, EcoRI, RsaI, Ksp221, and BstX21 showed the same of 700 bp band in Korean and Chinese arkshell. The phylogenetic tree inferred from PCR-RFLP pattern comparsion in Korean arkshell was different that the distance between Dukyang/Gamak/Taean and Namhae/Jinhae was approximately 7. In particular, the distance between Korean and Chinese arkshell was 25. Consequently, HinfI and HaeIII played an important role in a reliable molecular tool for rapid discriminating Korean and Chinese arkshell, as well as a intra-species in Korea.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2006.05a
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• pp.264-266
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• 2006

• Korean Journal of Fisheries and Aquatic Sciences
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• v.25 no.3
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• pp.171-175
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• 1992

In 1991, specimens of the arkshell, Scapharca broughtonii of Arcidae(Ptriomorphia, Mollusca) were collected from bottom culture bed at Namhae Island in Korea. The chromosomes were examined in the colchicinetreated cells of trochophore larva based on the air-drying method. Diploid number of the chromosome was 38 which were classified as metacentrics(pairs 5, 8, 13), meta or submetacentrics(pairs 6, 7), submetacentrics(2, 3, 9, 10, 12, 15, 16, 17, 18, 19) and subtelocentrirs(pairs 1, 4, 11, 14). No telocentric chromosome was observed.

• The Korean Journal of Malacology
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• v.28 no.3
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• pp.269-274
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• 2012

The genetic variation of Ark Shell, Scapharca broughtonii black was estimated using six polymorphic microsatellite (MS) loci in 443 individuals collected from five populations in Korea. The mean numbers of alleles per locus in five populations were 10-28. The mean number of alleles per locus in Jinhae Hatchery (JHH) population showed the least value as 15.5, but that in Gangjin (GJ) population showed the most value as 20.3. The mean expected heterozygosity in Saryangdo (SR) population showed the least value as 0.817, but that in Gangjin (GJ) population showed the most value as 0.831. In Jinhae hatchery(JHH) population, the mean expected heterozygosity was 0.822, there was no significant difference from those of wild population. The $F_{ST}$ values in Gangjin (GJ) population showed significant difference from those of the other populations, which revealed Gangjin (GJ) population is genetically different from the other populations. The $F_{ST}$ values among Jinhae Hatchery (JHH) population, Jinhae (JH) population and Saryangdo (SR) population showed lower values than the others, which implies there was a gene flow among these three populations. The $F_{ST}$ value and genetic distance between Jinhae (JH) population and Saryangdo (SR) population showed the least value as 0.0001 and 0.0386, indicating that these two populations were genetically the same.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.2
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• pp.297-304
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• 1997

Morphological and Benetic comparision were studied for the arkshell populations of Korea and China. The shell was collected from commercial arkshell bed in Jinhae Bay, Korea and from an hatchery in Young Seong, China. Shell Parameters, number of radial ribs and random amplified polymorphic DNA (RAPD) band were measured. The two populations had morphological and genetic differences. There was significant morphological difference $(P\leq0.05)$ in the ratio of the longest radial rib to the shell length. Posterior parts of the Chinese arkshell were more elongated than those of the Korean arkshell. Number of radial ribs were $36\~41$ for the Korean arkshell and $39\~43$ for the Chinese arkshell. RAPD markers generated tty each of 19 primers were $2\~6$ bands. Genetic diversity between the two Populations was clear since the genetic similarity was very low, not exceeding 0.29. The genetic similarity among the Korean arkshells $(0.58\~0.40)$ was higher than that of the Chinese arkshells $(0.48\~0.32)$.