• The Korean Journal of Malacology
• /
• v.13 no.2
• /
• pp.203-210
• /
• 1997

As a prioiminary study on usage of metabolic charateristics of the indicator species for indirect estimation of environmental water quality, effects of environmental pollutants on survival, filtration and oxygen consumption rates in Corbicula aeana were investigated at 17$^{\circ}C$ and $25^{\circ}C$ in 10 day afrer treatmint of pollutants. In case of glucose and complex fertilizer, the survival rates of the clams were 100% without any relation to individual sizes and water temperatures. In small sizes at $25^{\circ}C$, the survival rates of the clams by NH$_{4}$CI concentration were shown 95% at 10 mg/1 and 15mg/1, and 90% at 20mg/1, respectively. But the survival rate was 95%at 20 mg/1 of NH$_{4}$CI concentration in small size at 17$^{\circ}C$. The higher filtration and oxygin consumption rates were shown in small size at higher water timperatures(over $25^{\circ}C$), and generally filtration and oxygen consumption rates decreased with increase of glucose, complex fertilizer and NH$_{4}$CI concentrations, respectively. In general, effects of filtration and oxygen consumption rates at NH$_{4}$CI concentrations were shown slightly larger than those of glucose and complex fertilizer.

• The Korean Journal of Malacology
• /
• v.32 no.2
• /
• pp.67-71
• /
• 2016

In order to obtain a large number of fertilized eggs for seedling production, experiment was carried out examine effects of serotonin on spawning of the Pacific oyster Crassostrea gigas. The shorter response time to initial spawning in case of serotonin injection showed, the higher serotonin injected with 7.6-27 min. The response time to initial sperm releasing showed the same tendency with female. The highest response rates and eggs amount spawned were showed in the highest concentration. The serotonin injection had no effect on frequency of germinal vesicle breakdown (GVBD), fertilization and hatching rate.

• The Korean Journal of Malacology
• /
• v.32 no.1
• /
• pp.25-30
• /
• 2016

Growth-line analysis was carried out on 80 hard clam (Meretrix petechialis) from the Neolithic Age Eurwang-dong Shell Midden, Incheon, Korea, to determine the seasonality of shellfish collection and site occupation. Growth increments and the marginal index (MI) of the specimens were examined. And then the marginal index was compared to the monthly MI of modern specimens under the assumption that the growth pattern was the same as it is today. MI of the archaeological specimens ranged from 0.12 to 1.55 and was divided into four categories: < 0.63, spring; 0.63-0.76, summer; 0.76-0.89, fall; $${\geq}_-0.89$$, winter collection. As a result, 57 specimens (71.25%) of 80 specimens represented spring, 8 (10.0%) summer, 3 (3.75%) fall and 12 (15.0%) winter collection. The result indicates that shellfish could be collected year-round at the site with an emphasis on spring. Based on the size distribution of shells and the content of the midden, however, it seems that the midden site was not occupied permanently throughout the year but was used repeatedly but temporally for shellfish gathering and processing.

• The Korean Journal of Malacology
• /
• v.27 no.4
• /
• pp.345-351
• /
• 2011

Comparison of different morphological characteristics of bivalves is very useful for distinguishing species. Therefore, this study used a morphometric approach to document patterns of phenotypic change through the specimens of family Pinnidae inhabiting the bottom sediments at the coasts of An Thoi Archipelago (south-eastern Gulf of Thailand), in that way excluding intraspecific variations among different populations along a wide geographical range. It was revealed that individuals determined as Pinna trigonium separated from specimens of Pinna nigra and Atrina vexillum at high level, but P. nigra and A. vexillum were the single species A. vexillum, as it is assumed now. Also, it was found that both groups of P. trigonium individuals and A. vexillum specimens divided into tree subgroups unified the specimens with the similar morphometric parameters: small, medium and large within the populations, though there were no evident divisions into subgroups in the size distributions of the populations. In addition to the interspecific morphological variations, the species also showed significant intraspecific morphological variations even in the same population. Most probable reason for the appearance of the intraspecific morphological variations and division of all specimens into size-specific subgroups in the population is the fact that the growth of Pinnidae bivalves is not isometric.

• The Korean Journal of Malacology
• /
• v.27 no.4
• /
• pp.299-306
• /
• 2011

This paper examines relation between growth of adult top shell and their selectivity over different marine algae. For the study the top shell density and the algal species in different depth were surveyed by SCUBA. To test selectivity over different types of algae, five algal species including Ecklonia cava, Undaria pinnatifida, Ulva spp, Gelidium amansii and Sargassum spp were provided to top shells in indoor water tank condition. In the field survey, the wet weight of Ecklonia cava was significantly (r = 0.612, p < 0.05) correlated to the shell length (SL) of top shell. In the indoor water tank experiment conducted over 12 hours after sunrise, adult top shell (SL > SL 4.5 cm) tended to select Ecklonia cava and Undaria pinnatifida, which are common and abundant algal in the subtidal waters in Jeju Island. Our field survey and the indoor experiment suggest that E. cava and U. pinnatifida could be food preferred by adult top shell in its habitat.

• The Korean Journal of Malacology
• /
• v.26 no.1
• /
• pp.79-84
• /
• 2010

A morphological and ultrastructural study on the prostate of a land snail Nesiohelix samarangae was conducted. The prostate of Nesiohelix samarangae is a tubular gland connected with the large hermaphrodite duct. The lining of the prostate tubules possesses two distinct types of epithelial cells, one secretory and the other non-secretory. The secretory cells contained numerous secretory granules in various sizes and electron density. Most of the secretory granules showed light electron density but some of them showed heavy density. The ciliated cells were non-secreting cells situated only toward the lumen of the tubules and appeared as ordinary epithelial lining cells. The ciliated cells of the epithelium extensively interdigitate with each other and their apical surfaces had numerous cilia and microvilli. The bases of the ciliated cells did not reach the basal region of the secretory cells.

• The Korean Journal of Malacology
• /
• v.26 no.1
• /
• pp.85-89
• /
• 2010

Distribution of Cephalopods was investigated in the Yellow Sea, Korea from February, 2006 to November, 2008. The species composition of cephalopods, consisting of 14 species and 19,789 individuals has been identified. The dominant species of the Yellow sea was Euprymna morsei. The dominant species of the northern part, middle part and southern part were Todarodes pacificus, Loligo spp. and Loligo beka.

• The Korean Journal of Malacology
• /
• v.30 no.3
• /
• pp.249-258
• /
• 2014

Phytoplankton species composition and ecological index (diversity, evenness, richness and dominance) were analysed from April 2013 to March 2014 at 10 stations of cupped oyster, Crassostrea gigas culture area in Iwon coast, Korea. Seasonal and positional variation of phytoplankton standing crops, biomass, dominant species and water quality were distinctively different according to occasionally inflow of Iwon dam reservoired water. The composition of phytoplankton species were Bacillariophyceae 98, Dinophycease 22, Chlorophycease 13, Cyanophyceae 8, Silicofalgellate 4, Euglenophyceae 2, Cryptophyceae 1 species. The most dominant species was Bacillariophyceae as 64.0%. The highest biomass of phytoplankton recorded in September as $40,910{\times}10^3$ cell/L at the station 1, near from inland water inflow area. Ecological indices (diversity, richness, evenness, and dominance index), used for structural change of phytoplankton community and water quality (temperature, dissolved oxygen, salinity) showed difference of spatiotemporal property also.

• The Korean Journal of Malacology
• /
• v.30 no.3
• /
• pp.197-210
• /
• 2014

Single nucleotide polymorphisms (SNPs) are widely acknowledged as the marker of choice for many genetic and genomic applications because they show co-dominant inheritance, are highly abundant across genomes and are suitable for high-throughput genotyping. Here we evaluated the applicability of SNP markers developed from Crassostrea gigas and C. virginica expressed sequence tags (ESTs) in closely related Crassostrea and Ostrea species. A total of 213 putative interspecific level SNPs were identified from re-sequencing data in six amplicons, yielding on average of one interspecific level SNP per seven bp. High polymorphism levels were observed and the high success rate of transferability show that genic EST-derived SNP markers provide an efficient method for rapid marker development and SNP discovery in closely related oyster species. The six EST-SNP markers identified here will provide useful molecular tools for addressing questions in molecular ecology and evolution studies including for stock analysis (pedigree monitoring) in related oyster taxa.

• The Korean Journal of Malacology
• /
• v.30 no.3
• /
• pp.177-187
• /
• 2014

Mussels have been commonly used in bioassay for quality assessments of environment. Moreover, several standard protocols for the developmental bioassay of bivalves have been proposed. In this study, the EC50 of polycyclic aromatic hydrocarbons (PAHs) was determined using mussel, Mytilus galloprovincialis embryonic developmental bioassay. To determine the sensitivity of M. galloprovincialis, their fertilized eggs were exposed to five PAHs (2-metylnaphthalene, fluorene, dibenzothiophene, phenanthrene, pyrene). The EC50 of 2-metylnaphthalene, fluorene, dibenzothiophene, phenanthrene, and pyrene were 232, 273, 67.9, 43.2, and $33.1{\mu}g/L$, respectively. The overall sensitivity of M. galloprovincialis in the present developmental bioassay was similar to or more sensitive than that of other marine organisms commonly used in aquatic bioassays. The results of this study could be provide with fundamental data of setting standard for protection of marine life and or can use prediction the aquatic toxicity of PAHs.