• Animal Systematics, Evolution and Diversity
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• 제33권3호
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• pp.169-175
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• 2017

In the northwestern Pacific region, the pen shell (Atrina pectinata) is a widely distributed bivalve and economically important in fisheries. Recently, stock of this species has been greatly reduced due to overexploitation and marine pollution, which arouses interest in conservation. Studies on genetic and taxonomic entities of pen shells have not been tried in Korea, which makes difficult to take measures for effective conservation of this marine resource. In this study, we investigated mitochondrial genetic polymorphism of pen shells collected from 4 locations in Korea and Japan using cytochrome c oxidase I (COI) gene sequences. A total of 39 haplotypes were identified among 86 individuals of pen shell. Although only 5 haplotypes were shared, no significant genetic differentiation was observed between Korean and Japanese populations. These results suggest that pen shell populations of these regions share an ancestral population which might have experienced expansion during the Pleistocene, but gene flow must have been highly restricted after expansion.

• 한국패류학회지
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• 제22권2호
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• pp.167-173
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• 2006

The embryos of marine bivalves have been commonly used in bioassays for quality assessments of marine environments. Although several standard protocols for the developmental bioassay of bivalves have been proposed, only a few trials for application of these protocols in environmental assessments or for the development of a new protocol with Korean species have been conducted. As such, there is a strong need to establish standard bioassay protocols with bivalves commonly found in Korean waters. To determine the sensitivity of Mytilus galloprovincialis to establish a standard bioassay, their fertilized eggs were exposed to six metals (Ag, Cd, Cr, Cu, Ni, and Zn). The order of biological impact was Ag > Cu > Ni > Zn > Cr > Cd and their lowest observed effective concentration were 5, 16.4, 25.4, 142, 187 and 1,500${\mu}g/l$, respectively. The proportion of normal larvae appeared to decrease linearly with the logarithm of each toxicant concentration within the tested range. The average values of median effective concentrations $(EC_{50})$ from the triplicate experiments for Ag, Cd, Cr, Cu, Ni, and Zn were 6.8, 1,797, 786, 16.6, 68.1, and 139.2${\mu}g/l$, respectively. There was a more than 100-fold difference in $EC_{50}$ values of Cu and Cd. The value of $EC_{50}$ or median lethal concentration of Cu was within the range observed for other bivalve developmental bioassays. The overall sensitivity of M. galloprovincialis in the present developmental bioassay was also similar to that of other marine organisms commonly used in aquatic bioassays (e.g. sea urchins, oysters). Hence, the bioassay using the embryo of M. galloprovincialis is considered to be a useful tool to monitor and evaluate the quality of marine aquatic environments.

• Ocean and Polar Research
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• 제33권4호
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• pp.421-434
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• 2011

Although thermal effluent from coastal power plants affects marine ecosystems, few studies have examined the spatiotemporal distribution of macrobenthic communities in a coastal area of Korea with thermal discharge. This study analyzed the species composition and abundance of a macrobenthic community in relation to environmental variables for a period of 1 year. In total 334 macrobenthic faunal species were collected; the mean density was 3,221 ind/$m^2$. The number of species and the density of macrobenthic fauna increased with distance from the thermal discharge site. Cluster analysis indicated that the macrobenthic community could be divided into two groups: group I in shallow (< 30 m deep) and group II in the outer areas (> 30 m deep). Group I showed the lowest species density and diversity. Four polychaetes, including Magelona japonica, Spiophanes bombyx, Scolotoma longifolia and Chaetozone setosa, all of which have been dominant species since 1987, exhibited higher mean densities in the area distant from the thermal discharge (the outer and north areas). Conversely, the warm-adapted and opportunistic species, such as the amphipods Urothoe convexa and Mandibulophoxus mai, the bivalve Felaniella sowerbyi, and the polychaete Rhynchospio sp., were more abundant in the thermal discharge region. The results of this study indicate that thermal effluent influences macrobenthic communities in the shallow area, while other environmental variables, such as depth, sediment grain size, and TOC, are more important determinants of the macrobenthic communities in deeper regions (> 30 m deep).

• Journal of the korean society of oceanography
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• 제32권1호
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• pp.28-37
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• 1997

Two marine bivalve shells were collected from the eastern and western coastal regions of Korea, respectively. Stable oxygen and carbon isotope profiles are constructed using the incremental sampling along the axis of maximum growth to provide the continuous ${\delta}^{18}$O and ${\delta}^{13}$C records, which register the physical, biological and chemical properties of seawater where the organisms live. Cycles in the ${\delta}^{18}$O profiles are interpreted as annual along with the identification of annual growth bands; the maximum ${\delta}^{18}$O values correspond with the coldest temperature of seawater whereas the minimum ${\delta}^{18}$O values with the warmest temperature. The primary control on the amplitude of the ${\delta}^{18}$O profiles is seasonal variation of seawater temperature. The offset of the baseline between ${\delta}^{18}$O values of the two specimens is attributed to differences in both temperature and seawater ${\delta}^{18}$O values between two localities. The ${\delta}^{13}$C profiles show the similar seasonality of carbon cycling associated with phytoplankton productivity. The offset in the ${\delta}^{13}$C profiles between two specimens may be, as in the case of oxygen isotope profile, attributed to the different ${\delta}^{13}$C value of the seawater DIC (dissolved inorganic carbon) between the western coast and the eastern coast. Relationships between the shell isotopic composition and the coastal water properties of shell growth are readily interpreted from the ${\delta}^{18}$O-${\delta}^{13}$C pair diagram of the shell isotope data, similar to the use of salinity-${\delta}^{18}$O diagram for identifying water masses. The preliminary stable isotope results of this study suggest that mollusk shell isotope geochemistry may be useful to monitor the properties of water masses in the coastal and inner shelf setting around Korea and improve the interpretation of paleoceanography, provided the fossil mollusks are well preserved.

• Fisheries and Aquatic Sciences
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• 제5권3호
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• pp.183-190
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• 2002

To determine the effect of body size on the clearance rate and ingestion rate of small intertidal bivalves, Glauconome chinensis, feeding experiments were conducted on individuals of 12 different size classes, from 4 to 16 mm in shell length. Relationships between morphological parameters were also determined. The clearance and ingestion rates of G. chinensis responded similarly to their body size, ranging from 1.3 to 28.2 mL/hr/ind. and from 24.0 to 458.5, ${\mu}gC/hr/ind$., respectively. Both rates increased significantly (p<0.001) as shell length increased from 4 to 9 mm, although neither rate changed significantly when shell length was in the range from 12 to 16 mm. The weight-specific clearance rate $(CR_w)$ and ingestion rate $(IR_w)$ decreased with increasing body size, with values from 1.0 to 3.1 L/hr/g and from 17.9 to 51.3 mgC/hr/g, respectively. The $CR_w$ of G. chinensis was intermediate compared to those of larger bivalve species. The clearance rate (CR) relative to flesh dry weight (FDW) of G. chinensis were fitted well to the power function: $CR=0.43\times(FDW)^{0.71}\;(r^2=0.89)$. The exponent of fitting equation (0.71) of G. chinensis was higher than those of Mytilus edulis (Walne, 1972), Crassostrea gigas (Walne, 1972), and Placopecten magellanicus (MacDonald and Thompson, 1986).

• 한국수산과학회지
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• 제52권1호
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• pp.27-34
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• 2019

The seasonal and spatial variation of pathogenic Vibrio species, such as V. parahaemolyticus, V. vulnificus, V. alginolyticus, and V. cholerae were investigated in seawater and in bivalves off the Gyeongnam coast of Korea, which is an important area for shellfish production, during the period 2013-2016. V. parahaemolyticus, V. vulnificus, V. alginolyticus, and V. cholerae were detected in 12.1%, 5.2%, 15.4%, and 0.9% of seawater samples, respectively. V. parahaemolyticus, V. vulnificus, V. alginolyticus, and V. cholera were detected in 21.9%, 7.1%, 12.2%, and 0.0% of shellfish samples, respectively. The Vibrio spp. in seawater and bivalve samples were detected at high levels during the summer to early autumn; however, the levels were low during the winter. Therefore, their occurrence was seasonally dependent and correlated with high water temperature, which is also the biggest factor contributing to foodborne outbreaks associated with Vibrio. Relatively high detection rates of the strains were also found in the sea area that was continually exposed to inland wastewater. Our findings show that continuous monitoring is needed to reveal the patterns of occurrence of these pathogens from marine samples collected off the Korean coast, to reduce seafood-borne outbreaks caused by Vibrio.

• Ocean Science Journal
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• 제41권1호
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• pp.43-51
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• 2006

Concentration and distribution of Fe, Zn, Cu, Cd, Mn, Pb, Ni among subcellular fractions (cellular membrane structures and cytosol) and Zn, Cu, Cd among cytoplasmic proteins in the kidney and digestive gland of mussel Modiolus modiolus living along a polymetallic concentration gradient were studied. It was found in the kidney of M. modiolus from contaminated sites that the Fe percent increased in the "membrane" fraction, whereas Zn, Pb, Ni and Mn percent increased in the cytosol compared to the kidney of the control mussel. Note kidney cytosol of M. modiolus from clean and contaminated sites sequestered major parts of Cu and Cd. In the digestive gland of M. modiolus from contaminated sites Fe, Zn, Cd, Mn, Ni percent increased in the "membrane" fraction, whereas Cu, Pb percent increased in the cytosol compared to digestive gland of control mussel. Gel-filtration chromatography shows kidney of M. modiolus contains increased metallothionein-like protein levels irrespective of ambient dissolved metal concentrations. It was shown that the metal detoxification system in the kidney and digestive gland of M. modiolus was efficient under extremely high ambient metal levels. However, under complex environmental contamination in the kidney of M. modiolus, the metal detoxification capacity of metallothionein-like proteins was damaged.

• Fisheries and Aquatic Sciences
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• 제20권6호
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• pp.8.1-8.18
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• 2017

Background: Metallothionein (MT) is a multifunctional protein playing important roles in homeostatic regulation and detoxification of metals. Mollusk species have been considered as useful sentinel platforms for MT-based biomarker approaches, and they have been reported to display an extraordinary structural diversity of MT proteins. However, potential diversity of molluskan MTs has not been fully explored and recent updates have suggested the need of revision of evolutionary hypothesis for molluskan MTs. Results: Based on bioinformatic analysis and phylogenetic evidences, novel divergence mechanisms and paths were hypothesized in both gastropod and bivalve MT groups. Our analyses are suggestive of the taxon- or lineage-specific domain multiplication/duplication from the ancestral or prototypic MT. Diversification and selection of molluskan MTs might be driven by the needs for acquiring metal selectiveness, specialized novel function, and improved capacity of metal detoxification under environmentally stressed conditions. Conclusion: The structural diversity and variations of molluskan MTs are significantly larger than previously understood. Undoubtedly, molluskan MTs have undergone dynamic divergent processes in their evolutionary histories, giving rise to the great diversity of domain structures in extant MT isoforms. Novel evolutionary paths for molluskan MTs newly proposed in this review could shed additional light onto the revision of the hypothesis for evolutionary differentiation of MTs in the molluskan lineage.

• 한국수산과학회지
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• 제35권6호
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• pp.557-562
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• 2002

This study was to estimate population growth parameters of the freshwater bivalve, Corbicula (Corbiculina) papyacca (Heude) in Korea. Samples were collected from Jojong stream in Chungpyeong from September 1999 to August 2000. Ages were determined from the ring of shell, The shell length of the samples ranged from 4,2 mm to 28.1 mm, The ring on the surface of shell was formed once a year from January to March, Marginal increment analysis of shell rings indicated that annuli were formed in June. Spawning period was estimated to be May to August with a peak between June and July through fatness analysis, and thus rings were considered to be true annual marks. Von Bertalanffy's growth parameter were estimated from a nonlinear method with the value of logical maximum shell length ($L_{propto}$) was 34,36 mm, K was 0.1531/year, logical age of shell length 0 ($t_{0}$) was -0,5246 year, and logical maximum total weight ($W_{propto}$) was 11.42 g.

• 한국패류학회지
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• 제29권4호
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• pp.377-380
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• 2013

This study investigated concentration of metal ions in sediment and intersexuality in Polymesoda erosa and Lutraria lutraria. Samples were collected from five areas of Ha Long Bay in October, 2012. The concentration of metal ions showed that Al ($37390.0{\pm}11816.5mg/kg$) was highest and Mn ($360.4{\pm}101.4mg/kg$) was second high concentration. Cd ($0.04{\pm}0.05mg/kg$) was lowest. The intersexuality was 14.3% in P. erosa and 9.1% in L. lutraria that observed only in female.